National Aeronautics and Space Administration

Neil A. Armstrong Flight Research Center

Research, Technology, 

and Engineering 

Accomplishments

	

	



	

	


www.nasa.gov NASA/TM-2014-218336
2 ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014

From the Director: 

Research and Engineering Directorate

It’s with great pleasure that I endorse the 2014 Neil A. Armstrong 

Flight Research Center’s Research, Technology, and Engineering 

Accomplishments Report. The talented personnel at Armstrong are 

devoted to making meaningful and significant contributions to the 

important mission that NASA provides for the Nation. The researchers, 

engineers, and scientists at Armstrong continue a long, rich legacy of 

creating innovative approaches to solve some of the difficult problems 

and challenges facing the aerospace community. 

From advanced, lightweight sensing systems to efficient rocket 

nozzle research to the safe, routine operation of unmanned systems, 

the work represented in this report highlights the agility of Armstrong 

to develop technologies embedded in each of NASA’s core missions and, 

more importantly, technologies that bridge across missions. We’ve long 

considered one of our key strengths to be the ability to identify emerging 

yet innovative tools, techniques, and technologies that may be languishing in the development process and then rapidly move them into flight 

evaluation so that we can quickly identify their strengths, shortcomings, 

and potential applications.

This report presents a brief summary of the technology work of 

the Center. It also contains contact information for the associated 

technologists responsible for the work. Don’t hesitate to contact them 

for more information or for collaboration ideas.

Bradley C. Flick 

Director for Research and Engineering
ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014 3

From the Center Chief 

Technologist

I am pleased to present this report of accomplishments at NASA’s 

Armstrong Flight Research Center. Our Center draws on a rich history 

of performance, safety, and technical capability spanning a wide variety 

of research areas involving aircraft, electronic sensors, instrumentation, 

environmental and earth science, celestial observations, and much more. 

Our dedicated innovators not only perform tasks necessary to safely and 

successfully accomplish Armstrong’s flight research and test missions but 

also support NASA missions across the entire Agency.

From concept development and experiment formulation to testing, 

our engineers and scientists craft creative solutions that advance emerging 

technologies. At the same time, meticulous testing and analysis protocols 

ensure that we gather critical data to achieve continuous advancements for 

core NASA capabilities. 

The information in this report demonstrates how our talented 

personnel create and refine innovative flight research techniques that encompass all phases of flight projects, from highly developed design through 

development, fabrication, and operations processes. Through this ongoing 

refinement, we continue to expand our world-class capabilities, which 

include an expert work force, unrivaled facilities, aircraft and airspace, a 

diverse and exciting technology portfolio, and supportive infrastructure. 

Summaries of each project highlighting key results and benefits of the 

effort are provided in the following pages. Technology areas for the projects 

include hyperelastic research and lightweight flexible aircraft, flight and 

ground experimental test technologies, fiber optic sensing, supersonic 

flight research, and more. Additional technical information is available in 

the appendix, as well as contact information for the Principal Investigator 

of each project. 

I am proud of the work we do here at Armstrong and am pleased to 

share these details with you. 

Armstrong welcomes opportunities for partnership and collaboration, 

so please contact us to learn more about these cutting-edge innovations 

and how they might align with your needs. 

David Voracek

Center Chief Technologist

Supporting this R&D 

network is a range of 

assets:

More than a dozen piloted 

and autonomous airborne 

laboratories that benefit from 

excellent year-round flying 

weather

An aircraft integration facility 

that offers extensive simulation 

capabilities 

A flight loads laboratory 

that conducts thermal and 

mechanical load studies, 

including ground vibration 

testing of structural components, 

instrumentation, and complete 

flight vehicles

Fabrication, machine, and sheetmetal shops whose master 

craftsmen frequently work with 

exotic alloys and composites

A unique operations facility with 

more than 210,000 square feet 

of hangar space, conference 

accommodations, and storage, 

making it ideal for collaboration 

among visiting researchers and 

industry
4 ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014

Contents

PROJECT SUMMARIES

Hyperelastic Research/Lightweight Flexible Aircraft

Adaptive Compliant Trailing Edge (ACTE) Flight Experiment ............................................................................ 6

Fundamental Hyperelastic Material Study ........................................................................................................ 7

X-56A Multi-Utility Technology Testbed (MUTT)................................................................................................ 7

Robust Virtual Deformation Control of the X-56A Model .................................................................................. 8

Real-Time Structural Overload Control via Control Allocation Optimization..................................................... 8

Inverse Finite Element Method (iFEM) Investigation for Adaptive Structures ................................................... 9

Active Control of Tailored Laminates ................................................................................................................. 9

Active/Adaptive Flexible Motion Controls with Aeroservoelastic System Uncertainties ................................... 10

Flight and Ground Experimental Test Technologies

	
	



 ................................................................................................................... 11

Vehicle Integrated Propulsion Research (VIPR) ................................................................................................. 12

Dynamic Inertia Measurement Method ............................................................................................................. 12

Acoustic Diagnostics of Turbofan Health Monitoring ........................................................................................ 13

Hot Ground Vibration Tests ............................................................................................................................... 13








	
 ................................................................................... 14

Fiber Optic Sensing

Compact FOSS (cFOSS) ................................................................................................................................... 15

Hybrid FOSS (HyFOSS) ..................................................................................................................................... 16

Smart Sensing Using Wavelets ......................................................................................................................... 16

Determining Applied Load Data with Strain Measurements ............................................................................. 17

Strain Sensing for Displacement and 2-D Shape.............................................................................................. 17

Cryogenic FOSS (CryoFOSS) ............................................................................................................................ 18

High-Temperature Strain Sensing ..................................................................................................................... 18

Strain Sensing for Highly Elastic Materials........................................................................................................ 19

Health Monitoring of Flight Structures .............................................................................................................. 19

Supersonic Flight Research 


	
	

 ............................................................................................................. 20

!"#



$

	
%#&
'$
!	%' ..................................................................... 21

*
$
+

:
;
	

*; ....................................................................................... 21

#
&
<&



<
 ............................................................................................ 22

'
'
"+=


'= .......................................................................................... 22

Airborne Schlieren Imaging System (ASIS) ....................................................................................................... 23

Collision Avoidance Technologies

Global Elevation Data Adaptive Compression System (GEDACS) .................................................................... 24

Improved Ground Collision Avoidance System (iGCAS) for UAVs .................................................................... 25

Multi-Level Autonomous Piloting System (MAPS) ............................................................................................ 25
ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014 5

Avionics and Instrumentation Technologies

Platform Precision Autopilot (PPA) .................................................................................................................... 26

'
	

%#

$


'%
&
	
:
:



'> .................. 27

Distributed Aerostructural Sensing and Control................................................................................................ 27

Portable Data Acquisition SysTem (PDAT) ........................................................................................................ 28

;
>"

	

 ............................................................................................................................... 28

Airborne Research Test System, Fourth Generation (ARTS IV) ......................................................................... 29

;?
@


*+

+

'&
>

%

+

 ............................................. 29

Hypersonics and Space Technologies

Air Launch from a Towed Glider ........................................................................................................................ 30 

'


!	#
+
;BB
'!;................................................................................................................ 31

Advanced Control Method for Hypersonic Vehicles ......................................................................................... 31

Adaptive Guidance Algorithms for Hypersonics ............................................................................................... 32

High-Altitude Atmospheric Reconstruction....................................................................................................... 32

Structurally Integrated Thermal Protection System (SITPS) ............................................................................. 33

	







';%<%
J
@ .......................................................................................................................... 34

Turbo-Electric Distributed Propulsion Test Stand ............................................................................................. 35


	+

*>
!



J
;

<	
*>
K+ ............................................................. 35

Unmanned Refueling for UAVs .......................................................................................................................... 36

Air-to-Air UAV Aerial Refueling .......................................................................................................................... 36

Data Fusion to Estimate Vortex Location for Drag Reduction in Formation Flight ........................................... 37

Optimized Lift for Autonomous Formation Flight (OLAFF) ................................................................................ 37

Peak-Seeking Control for Trim Optimization ..................................................................................................... 38

Low-Carbon Propulsion Technology

Alternative Fuels’ Effects on Contrails and Cruise Emissions (ACCESS) Flight Experiment ............................ 39

Engineering Successes

Dope on a Rope 2: Development of a Dream Chaser Aero Tow Simulation ..................................................... 41

SAFE-Cue to the Rescue! ................................................................................................................................. 42

#
"
$Y
'
;>
*+



............................................................................... 42

'
&
	



*+


 ......................................................................................................... 43

Abort!...In the Event of an Emergency............................................................................................................... 44

Portable Data Acquisition SysTem (PDAT): Making Ideas Reality ..................................................................... 45

Z
J




+ ................................................................................................................................ 45

!#
+


	 .......................................................................................................................................... 46

Flying an Airplane Like a Rocket ....................................................................................................................... 47

Masking the Sun and Scoping the Problem...................................................................................................... 47

Precision Path Autopilot (PPA) .......................................................................................................................... 48

Appendix ......................................................................................................................................... 49
6 ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014

	




Hyperelastic Research/Lightweight 

Flexible Aircraft

Armstrong engineers are pioneering new research 

in aircraft design and modeling. Researchers are 

experimenting with revolutionary hyperelastic wing 

control technologies that can reduce weight, improve 

					!"	#	

cutting-edge research involves techniques, models, and 

$	$		!			%&$	$$'-

tion.

Flight projects at Armstrong rely on high-performance 

aircraft that can support research on lightweight structures 

	'	$	#$%				

environmentally friendly transport aircraft. This work has 

$($	(	!%#			%	)"	

Armstrong’s R&D capabilities in this area also can be 

applied to other vehicles, such as supersonic transports, 

large space structures, and hypersonic vehicles.

Adaptive Compliant Trailing Edge (ACTE) 

Flight Experiment 

The ACTE experimental flight research project is investigating whether 

advanced flexible trailing-edge wing flaps can both improve aircraft 

aerodynamic efficiency and reduce noise associated with takeoffs and 

landings. The experiment involves replacing the conventional aluminum 

wing Fowler flaps of a Gulfstream III (G-III) research testbed aircraft 

with advanced, shape-changing, composite material flaps that form 

continuous bendable surfaces. The primary goal of the experiment is to 

collect flight data about the integration and reliability of the composite 

wing flaps.

Work to date: The G-III has been converted and instrumented into a 

test platform. The flexible structures have been developed and tested for 

aircraft applications.

Looking ahead: Flight testing is scheduled to begin in fall 2014. The 

new flexible wing flaps have arrived at Armstrong, and engineers are 

preparing them for ground vibration testing, fit checks, and eventual 

installation. Ultimately, the goal is to work toward developing a wing that 

incorporates this design from the start, rather than flap integration as has 

occurred to date. 

Partners: FlexSys Inc. designed and built the revolutionary experimental 

flaps under contract to the U.S. Air Force Research Laboratory. NASA’s 

Environmentally Responsible Aviation Project is supporting the NASA work.

Benefits

Innovative: Advances compliant structure 

technology for use in aircraft to significantly 

reduce drag, wing weight, and aircraft noise

Economical: Reduces drag and increases 

fuel efficiency through the use of an advanced 

compliant structure

Applications

Aircraft control surfaces

Helicopter blades and wind turbines
ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014 7

1$	2$	$	
	

This research is part of an innovative effort to use hyperelastic materials 

to produce flexible and seamless aircraft structures that reduce drag 

and minimize acoustic noise. Hyperelastic materials, such as rubber, 

have a non-linear stress-strain relationship, which often complicates 

the modeling process. Researchers are investigating the properties of 

hyperelastic materials and developing improved finite element analysis 

(FEA) models. This technology has been shown to improve aircraft 

aerodynamic efficiency and reduce airport-area noise generated during 

takeoffs and landings. 

Work to date: The Armstrong development team has fabricated the 

biaxial strain test hardware and completed initial bubble test planning. 

The team is working to obtain biaxial strain properties and develop 

an FEA model that simulates the material properties and failure 

characteristics. 

Looking ahead: The team will fine-tune the modeling in 2014 by 

comparing the predicted output to an actual bubble test of the material. 

Benefits

Economical: Use of hyperelastic material 

increases fuel efficiency by reducing drag.

Quieter: ;$
>+
:#




associated with takeoffs and landings both 

in the aircraft cabin and on the ground.

Applications

Aircraft wing flaps

Helicopter blades

Motor vehicles, trains, and ships

3&45
	$&$	#$%	(	

67

Longer and more flexible wings are considered crucial to the design 

of future long-range, fuel-efficient aircraft. Because these wings are 

more susceptible to flutter and the stress of atmospheric turbulence, 

NASA is investigating key technologies for active flutter suppression and 

gust-load alleviation. The goal of the X-56A MUTT project is to advance 

aeroservoelastic technology through flight research using a low-cost, 

modular remotely piloted experimental aircraft. The aircraft is being 

tested using flight profiles where flutter occurs in order to demonstrate 

that onboard instrumentation not only can accurately predict and sense 

the onset of wing flutter but also can be used by the control system to 

actively suppress aeroelastic instabilities. 

Work to date: Flight tests in 2013 provided validation of the flight 

vehicle systems and paved the way for flights in 2014 to validate fluttersuppression techniques on highly flexible structures. The Armstrong 

team has provided oversight regarding airworthiness and flight safety as 

well as operations and range support.

Looking ahead: Goals include: (1) maturing flutter-suppression 

technologies, (2) reducing structural weight to improve fuel efficiency, 

and (3) increasing aspect ratio by 30 to 40 percent to reduce 

aerodynamic drag.

Partner: Air Force Flight Research Laboratory

Benefits

Advanced: Enables construction of longer, 

lighter, more flexible wings for a variety of 

crewed and remotely piloted aircraft

Configurable: Enables a vast array of 

future research activities for wing sets, tail 

sections, sensors, and control surfaces

Applications

Lightweight commercial aircraft

High-altitude surveillance platforms
8 ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014

	


 Hyperelastic Research/Lightweight Flexible Aircraft

Robust Virtual Deformation Control 

	#	3&45
	$		

An Armstrong research team has developed a virtual deformation 

controller designed to actively suppress flutter on the X-56A experimental 

aircraft by changing wing shape. A remotely piloted aircraft with a stiff 

body and flexible detachable wings, the X-56A was developed for the sole 

purpose of testing various active flutter-suppression technologies. As part 

of its sensor array, the aircraft wings will be instrumented with fiber optic 

sensors that can measure strain at thousands of locations. The controller 

will use these sensors in an adaptive feedback system to automatically 

manipulate the trailing edge control surfaces and body flaps to suppress 

flutter. A robust modal filter solution has been developed for wing damage 

assessment and robust flight control. The solution adaptively finds strain 

anomalies in the structure and reports them to the control system. 

Work to date: The team has validated the controller for both flutter 

suppression and shape control in simulations using X-56A models that 

contain all six rigid-body degrees of freedom, flexible modes, 10 control 

surfaces, and actuators. Simulations have shown that the shape controller 

can affect the global angle of attack and achieve drag changes.

Looking ahead: Next steps involve non-linear simulations and in-flight 

experimentation.

Partner: Air Force Flight Research Laboratory

Benefits

More design freedom: Allows designers to 

consider lighter/larger wing profiles

Safer flight: Reduces likelihood of losing 

control

Applications

Aircraft design and aeroservoelastic tailoring

Active flutter suppression

Loads and health monitoring

$&	
$	'$	$	

'	$	
$$	)

This control methodology utilizes real-time measurements of vehicle 

structural load to actively respond to and protect against vehicle 

damage due to structural overload. The innovation utilizes critical point 

load feedback within an optimal control allocation architecture that 

constrains the load at those critical points while still producing the 

control response commanded by a pilot. Specifically, the technology 

monitors the loads at critical control points and shifts the loading away 

from points at or near their limits.

Work to date: Using NASA’s Full-Scale Advanced Systems Testbed 

(FAST) aircraft, the Armstrong team targeted the aileron hinge 

connection as a critical control point. The experiment produced 

successful results in flight, limiting the aileron hinge moments to below 

a specified value while maintaining aircraft roll performance with 

minimal impacts to piloted handling quality ratings. 

Looking ahead: Future tests will employ more advanced and unique 

sensor technologies, such as fiber optic strain sensors, which will 

improve both the robustness of the approach as well as the ability to 

measure the load throughout the vehicle structure. This technology 

could open the door to truly novel approaches to vehicle and control 

system design, such as adaptive controls and reduced structural 

design margins. 

Benefits

Effective: Identifies the optimum control 

surface usage for a given maneuver for both 

performance and structural loading

Automated: Monitors and alleviates stress 

on critical load points in real time

Applications

Jet aircraft

Industrial robotics
ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014 9

'	1	$	#	617	

'%		
'	
	

This research project is evaluating an innovative technique that uses 

fiber optic strain sensors to measure structural deformations and 

full-field strains. An iFEM analysis reconstructs a deformed structural 

shape based on the strain measurement data simulated by FEM 

analysis to represent the in situ strain measurements. Mapping the 

iFEM displacement solution onto a full FEM model without the applied 

loading allows the complete fields of displacement, strain, and stress to 

be reconstructed to a high degree of accuracy. The innovation improves 

safety by enabling more efficient health monitoring of control surfaces 

and flexible structures. This project supports work on multiple flight 

research projects at Armstrong. 

Work to date: The team has completed and validated a onedimensional beam element test using a compliant slider mechanism. 

Looking ahead: Future plans involve developing and validating the 

algorithm on a full-size flight test article.

NASA Partner: Langley Research Center

Benefits

Accurate: Enables accurate full-field 

structural shape and strain measurement

Economical: Uses a minimal number of 

sensors to recreate the full-field structural 

deformations and strains

Applications

Aircraft wing flaps

Helicopter blades

Wind turbines

Motor vehicles

Trains

Ships and submersibles

Active Control of Tailored Laminates

Part of a proposed suite of technologies to enable a fully morphing 

seamless wing, this effort focuses on tailoring composite materials to 

enhance structural response and generate out-of-plane deflections 

using in-plane forces. Composite structures employ embedded fibers 

in different directions to increase strength. This research seeks to 

investigate the use of tailored composites in these types of applications. 

Work to date: An analytical feasibility study completed in 2013 

determined that in-plane loading can generate significant out-of-plane 

displacement, effectively yielding wing twist. Also determined was the 

degree of structural interaction of stiffeners and how to mitigate the 

suppression of structural response. 

Looking ahead: Future work will concentrate on enabling continuous 

outer mold line structures that can change shape. This revolutionary new 

approach for aircraft design will improve performance and fuel efficiency 

in numerous ways, as seamless wings would reduce drag and streamline 

and simplify an airplane’s maneuverability.

Benefits

Economical: Increases fuel efficiency by 

reducing drag

Robust: Features a simpler wing design 

without control surfaces that is easy to 

maintain and less likely to need repair

Applications

Commercial aircraft

General aviation aircraft

Military transport aircraft
10 ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014

	


 Hyperelastic Research/Lightweight Flexible Aircraft


'8
'	1$9($		 

$	;#	
'$	
	 

		

Most aeroservoelastic analyses of modern aircraft have uncertainties 

associated with model validity. Test-validated aeroservoelastic models 

can provide more reliable flutter speed. Tuning the aeroservoelastic 

model using measured data to minimize the modeling uncertainties 

is an essential procedure for flight safety. However, uncertainties still 

exist in aeroservoelastic analysis even with the test-validated model 

due to time-varying uncertain flight conditions, transient and nonlinear 

unsteady aerodynamics, and aeroelastic dynamic environments. For 

flexible motion control problems, a control law that adapts itself to 

such changing conditions is needed. Active and adaptive control of 

these coupled mechanisms is mandatory for stabilization and optimal 

performance in such time-varying uncertain flight conditions.

The primary objective of this research is to study the application of a 

digital adaptive controller to the flexible motion control problems. This 

can be achieved by introducing online parameter estimation together 

with online health monitoring. Structural response information at 

the selected sensor locations will be used for the online parameter 

estimation. The second objective of this research is to develop a simple 

methodology for minimizing uncertainties in an aeroservoelastic model.

Work to date: The team has modeled known uncertainties.

Looking ahead: Future activities involve further refinement of the 

models, which will involve flight tests currently planned for 2015.

Partners: Lockheed Martin Advanced Development Program has 

provided the X-56A FEM and test data. The Air Force Research 

Laboratory will provide X-56A vehicles and ground control systems. 

Other NASA Centers have contributed to this effort as has the University 

of Texas at Austin.

Benefits

Economical: Enables high-precision 

simulation prior to expensive flight 

tests

Smoother ride: Permits superior 

ride-quality control

Applications

Resulting models apply across a wide 

range of aircraft 

The cavernous interior of the Armstrong Aircraft Operations Facility.
ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014 11

	




Flight and Ground Experimental 

Test Technologies

A%		''	!%#	#	#	

continues to expand its world-class capabilities, 

with special expertise in research and testbed 

platforms, science platforms, and support aircraft. Researchers place particular emphasis on providing accurate 

!%#			#			%%	9&%	

!%#	'#$"

Described here are research projects that are seeking to 

increase safety, reduce costs, and dramatically decrease 

%		'$	"	
%<	;	'	

and validation (V&V) simulation test bench is particularly 

''			%	%($	;	$	

for multiple aircraft components. These models enable 

#%#&$	$		(			$	

		%$			#		($	;#	

hardware-centric test benches. 

$&		

Armstrong researchers have implemented in the control room a 

technique for estimating in real time the aerodynamic parameters that 

describe the stability and control characteristics of an aircraft. Typically, 

aerodynamic modeling is performed on recorded data after test flights 

and then used in simulations. The drawback with this approach is that 

if the collected data are not complete or of high quality, additional 

and costly flight tests must be scheduled. In this innovative approach, 

Armstrong’s real-time parameter estimation automates the process and 

runs during flight, enabling researchers in the control room to evaluate 

and adjust flight maneuvers to ensure data quality. The technology 

increases the efficiency and productivity of flight tests, as researchers 

can determine during the tests if they have collected the data needed for 

specific modeling simulations. 

Work to date: The technology is currently being used in Armstrong 

control rooms to evaluate data collected during test flights as well as 

in-flight maneuvers. 

Looking ahead: Researchers are continuing to improve the system 

display and are working to refine the way results are presented. A 

capability to compare the estimated parameters to preflight-predicted 

values is being added, which will make it possible to evaluate the 

aerodynamic effects of aircraft modifications.

Benefits

Automates data collection: Estimates in 

real time the parameters for aircraft stability 

and control

Improves data quality: Enables 

adjustments during flight tests to ensure 

correct data acquisition

Saves time and resources: Decreases 

the duration and number of flight tests

Applications

Aerodynamic modeling
12 ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014

	


 Flight and Ground Experimental Test Technologies

=#$	%	$	#	

6=7		

A major aspect of NASA’s propulsion health management development 

work is demonstrating and evaluating emerging technologies on 

operational engines. Harsh environment conditions within an engine 

present significant challenges for the integration and application 

of aircraft health management technologies. VIPR is a program for 

developing real-world tests to evaluate such emerging technologies. 

Work to date: The VIPR I tests occurred in 2011 at Armstrong and 

involved model-based performance estimation and diagnostic work. 

In 2013, follow-on VIPR II tests evaluated additional engine health 

management sensors and algorithms under nominal and faulted engine 

operating scenarios. 

Looking ahead: In upcoming VIPR III tests, researchers will inject 

volcanic ash into a commercially representative high-bypass turbofan. 

NASA sensors installed in the engine will measure how and where the 

engine degrades after several hours of exposure to low and moderate 

ash concentrations. The experiment will provide useful information 

to aircraft and engine manufacturers, airline operators, and aviation 

regulators as they evaluate the risks that ash hazards pose to aviation. 

Partners: VIPR partners include U.S. Air Force, Federal Aviation 

Administration, U.S. Geological Survey, Pratt & Whitney, GE Aviation, 

Rolls-Royce, The Boeing Company, Makel Engineering, and academia.

Benefits

Advances research: Accelerates the 

technology readiness level for aviation safety 

innovations

Increases safety: Enhances safety features 

implemented on aircraft to handle a wide 

variety of potentially dangerous conditions and 

situations

Applications

Detecting and diagnosing engine faults 

Testing health management technologies 

Designing fault-tolerant engines

>			#

Critically important inertia measurements are complex and expensive 

to obtain due to the extensive fixturing and custom instrumentation 

of conventional techniques. This research effort has validated a more 

efficient, less risky, and faster inertia measurement technique for 

aerospace vehicles. The dynamic inertia measurement method is based 

on conventional ground vibration testing methods, which are routinely 

performed in other types of aircraft testing. The basic concept is to 

compute the inertia properties and center-of-gravity location of an 

object by measuring all forces acting on the object and the rigid body 

motion caused by these forces. This innovation significantly reduces 

cost as it eliminates the complex and expensive fixturing and equipment 

used in conventional measurement techniques.

Work to date: A comparison to analytical measurement demonstrated 

that the theory is sound, although additional tuning of the algorithms will 

be required. Data produced from an “iron bird” demonstration test will 

help build confidence in the approach. 

Looking ahead: The team is working to compare the method to 

conventional approaches. The next project phase, testing on an 

aerospace vehicle, has not yet been funded. 

Partner: ATA Engineering, Inc., provided software and support for the 

testing.

Benefits

Less risky: Does not require the vehicle to 

be suspended, reducing risk and equipment 

needs

Faster: Dramatically decreases testing and 

approval times by weeks or even months

Applications

Airplanes and space vehicles (capsules and 

lifting-body spacecraft)

Automobiles and other large terrestrial vehicles
ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014 13

Acoustic Diagnostics of Turbofan Health 

%	

This unique innovation employs an array of external microphones to 

pinpoint faults within turbofan engines. The development team partnered 

with Armstrong’s Vehicle Integrated Propulsion Research (VIPR) 

effort by piggybacking onto an existing field test. After a successful 

demonstration, the project is now part of the VIPR program, which will 

fund the work going forward. 

Work to date: The team has achieved several significant technical 

accomplishments, most notably the successful recording of VIPR 

turbofan engine data with external microphones. In this particular 

test, bleed valve failures were induced at both high- and low-pressure 

compressor stages within an engine and the data were recorded. The 

team then developed software algorithms to identify engine faults 

within acoustic data and applied these algorithms to the recorded data, 

successfully identifying the bleed valve failures in the high-pressure 

stage. 

Looking ahead: Identifying faults at low-pressure stages will require a 

system with greater sensitivity; therefore, the team plans to use additional 

experimental recorded data to show how an array of microphones can 

detect quieter faults.

Benefits

Accurate: Uses an innovative array 

configuration to pinpoint the exact location of 

a fault within an engine

Efficient: Optimizes condition-based 

maintenance so that service occurs only when 

needed rather than at predetermined times

Improves safety: Identifies faults before 

they cause catastrophic damage

Applications

Aircraft engines, commercial rail, and trucks

Military land transport vehicles

Hot Ground Vibration Tests

Ground vibration tests or modal surveys are routinely conducted to 

support flutter analysis for subsonic and supersonic vehicles. However, 

vibration testing techniques for hypersonic vehicles are not as well 

established due to the thermoelastic interactions that can occur when 

high-temperature materials are incorporated into a hot structure 

that contains metallic components. In recent years, numerous hightemperature materials, new fabrication technologies, and sensors have 

been explored for hypersonic vehicle applications. A research team 

is working to develop a high-temperature modal survey to expand the 

research database for hypersonics and improve the understanding of 

such dual-material interactions. 

Work to date: Armstrong directed a program to test a carbon-silicon 

carbide (C/SiC) Ruddervator Subcomponent Test Article (RSTA) to 

support hypersonic material research. The RSTA has undergone 

numerous thermal, thermal-mechanical, and thermal-vibration tests. The 

team obtained good modal data at lower temperatures, but the off-theshelf, high-temperature accelerometers malfunctioned on the hotter 

region of the test article. The experiments yielded test data that will be 

useful for future work and launched a high-temperature accelerometer 

development effort.

Looking ahead: The research team has obtained custom-made and 

multiple other high-temperature accelerometers and is taking steps to 

understand, evaluate, and characterize their complexity and functionality 

in preparation for future thermoelastic vibration tests.

Benefits

Innovative: Expands the research 

database for hypersonics

Pioneering: Extends the understanding of 

the modal characteristic effects from high 

temperatures on hypersonic vehicles

Aids research: Contributes to the 

understanding of flutter behavior at high 

temperatures

Applications

Hypersonic vehicle research and design
14 ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014

	




Previous test bench

Flight and Ground Experimental Test Technologies

=		=$	6=?=7	@#	

Enhancements 

Armstrong engineers have developed a new simulation test bench for 

V&V of software and hardware for the F/A-18 aircraft. The new V&V test 

bench replaces a bench that was developed more than 30 years ago. 

Work to date: The new and more reliable bench is particularly 

innovative as it integrates reconfigurable software models for multiple 

aircraft components. These models enable high-fidelity simulations to be 

performed more easily and at significantly faster rates than were possible 

using the old hardware-centric test bench. In addition, this approach 

offers more accurate predictions of behavior. 

Looking ahead: The team plans to begin developing the capability to 

interface with a wide variety of other computers, which in turn will enable 

simulations of other 

aircraft such as the 

F-15 and systems 

with digital flight 

control systems.

Benefits

Rapid data collection: Operates at faster 

rates, allowing for more detailed modeling

Reconfigurable: Will accommodate other 

aircraft via software reconfigurations

Economical: Reduces the number of 

expensive flight tests

Applications

F/A-18 and F-15 aircraft

Electric aircraft motors and actuators

Control systems with redundant digital flight 

control systems

Simulation technicians install a boilerplate Dream 

Chaser canopy structure over the cockpit of a 

flight simulator in the simulation laboratory at 

NASA’s Armstrong Flight Research Center.
ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014 15

	




1(		
%

A%<	$		1(		
%	
	61

7	 

technologies offers unparalleled options for high-resolution sensing 

in applications that require a unique combination of high-powered 

%		$%#;%#	!9($		(	"	#		 

measures real-time strain, which can be used to determine two-dimensional 

and three-dimensional shape, temperature, liquid level, pressure, and loads, 

$			("	$$	'$						

!%#	#	<	($				;	$		(	

optics—not just in aerospace but also for civil structures, transportation, oil 

and gas, medical, and many more industries.

#	
%	#	$	(	@%%	%%	61@B7		$	

I		!	61>7	%		$&	$%-

rithms (100 samples/second). Engineers are continually seeking new ways 

of looking at information and determining what is important. Armstrong’s 

1

	#$%			$	#	"	M##					

determine shape, stress, temperature, pressure, strength, operational load, 

or liquid level, this technology offers ultra-fast, reliable measurements.

	1

	61

7

Armstrong researchers are reducing the FOSS technology’s size, power 

requirement, weight, and cost to effectively extend opportunities for 

broader fields of application. Unlike current commercially available 

systems, which are limited by the number of fibers that are interrogated 

simultaneously, Armstrong’s cFOSS technology maintains its multi-fiber 

capability (four or eight fibers) while providing a smaller overall form 

factor. FOSS is the size of a shoebox and weighs 28.5 pounds; cFOSS 

will be the size of a 6-inch cube and weigh less than 10 pounds. Each 

component within the system has been custom-designed specifically 

for miniaturization, thus reducing capital costs. As industries strive for 

ever smaller profiles, this miniaturization will be an important benefit 

for multiple markets. For example, small aviation UAVs would benefit 

significantly from this smaller, more compact, and lightweight package.

Work to date: In partnership with the AERO Institute, researchers have 

flown the cFOSS v1.0 system, a convection-cooled 5-lb version, on a 

small UAV, interrogating four fibers simultaneously.

Looking ahead: By the end of December 2015, cFOSS v2.0, with 

conduction cooling, will fly on an Antares rocket.

Benefits

Compact: Miniaturized size requires less 

associated hardware than existing systems.

Reliable: Components are customized 

for aggressive environments yet maintain a 

compact form factor.

Applications

Aeronautics and launch vehicles

Medical procedures

Oil drilling, wind energy, automotive testing, 

and industrial processes
16 ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014

	


 1(		
%

2(	1

	621

7		

The HyFOSS technique employs conventional continuous grating fibers 

and then overlays sections every 3 or 4 feet with “strong” gratings that 

can be sampled at higher rates. The new and stronger gratings can be 

sampled at rates up to 5,000 hertz (Hz), while the continuous grating 

sections continue to be sampled at the lower 100-Hz rate. This technique 

enables higher spatial resolution at specific targets without sacrificing 

resolution in other areas. The ultimate goal is to achieve sampling rates 

up to 20 kHz. This increased sampling capability would allow structural 

features related to high-frequency shock and/or vibration to be captured.

Work to date: The team began investigating the technique in early 

2013 after a request from NASA’s Kennedy Space Center to investigate 

the development effort required to increase the sample rate from 100 Hz 

to more than 20 kHz. To date, the OFDR technology does not have the 

capability to achieve these higher sample rates, though the possibility of 

fusing Wavelength Division Multiplexing (WDM) is feasible yet with limited 

spatial resolution. Combining the best of OFDR and WDM technologies 

into new hardware that utilizes the same optical fiber would allow for 

high spatial resolution with lower sample rates in addition to the ability to 

obtain high sample rates at strategically spaced points along the fiber. 

Looking ahead: Researchers are investigating a 40-foot fiber strand 

embedded with the new technology in the laboratory environment. The 

Armstrong team also is investigating the possibilities of pushing the 

overall sample rate to 20 kHz.

Benefits

More measurements: Offers higher 

sampling rates (up to 5 kHz) for specific 

portions of the fiber

Fast processing: Collects data at various 

resolutions without sacrificing speed

Applications

Aeronautics and launch vehicles


	
%	%	M'$

These further refinements to the FOSS technologies are focusing on 

smart sensing techniques that adjust parameters as needed in real 

time so that only the necessary data are acquired—no more, no less. 

Traditional FOSS signal processing is based on Fourier transforms that 

break up the length of the fiber into equal-length analysis sections. 

If high resolution is required along one portion of the fiber, the whole 

fiber must be processed at that resolution. Wavelet transforms make 

it possible to efficiently break up the length of the fiber into analysis 

sections that vary in length. If high resolution is required along one 

portion of the fiber, only that portion is processed at high resolution, and 

the rest of the fiber can be processed at the lower resolution.

Work to date: The team has developed a C-language prototype of a 

wavelet-based signal processing algorithm. This static form currently 

operates at half the speed of the Fourier-based algorithm, but it will be 

able to operate three to four times faster once optimized.

Looking ahead: Next steps involve developing an adaptive form of the 

wavelet algorithm and optimizing the code. An adaptive algorithm would 

automatically change the resolution of sensing based on real-time data. 

For example, when strain on a wing increases during flight, the software 

will automatically increase the resolution on the part of the fiber that is 

under strain.

Benefits

Improved efficiency: Offers precision 

measurement only where it is needed rather 

than on the entire fiber

Faster signal processing: Processes 

data at different resolutions for specific fiber 

segments

Applications

Strain sensing

Temperature measurements
ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014 17

Determining Applied Load Data with 


		

Armstrong researchers have developed a method for obtaining externally 

applied, out-of-plane operational load data on complex structures using 

surface in-plane strain measurements. This approach allows for efficient 

characterization of out-of-plane bending and torsional stiffness of 

structures. 

Currently, industry uses computational methods such as finite element 

analysis (FEA) to obtain operational load data for complex structures; 

however, this approach is time consuming and requires the structure 

to be broken down into small elements for analysis, a challenging task 

for structures with complex geometries. To obtain real-time load data, 

standard methods rely on the use of strain gauges on the structure, yet a 

costly and extensive calibration process must be performed prior to realtime analysis. This Armstrong-developed method saves time and is more 

efficient and accurate.

Benefits

Provides real-time data: Enables 

measurements outside test facilities and 

during operation 

Less expensive: Provides similar spatial 

resolution to that obtained from the more 

cumbersome, labor-intensive, and costly 

FEAs

More accurate: Improves accuracy of the 

simplified structural models

Applications

Aircraft wing analysis

Structural health monitoring for buildings, 

bridges, and ships


	
%		>$		

;&>$	6N&>7	
#

A gust of wind or aerial maneuvers can cause a large displacement 

in the 300-foot wingspan of a lightweight UAV during flight and is the 

known cause of at least one Helios UAV crash. Therefore, an Armstrong 

research team has designed an algorithm model that uses fiber optic 

structural strain measurements to determine deflection and 2-D shape. 

When combined with the other elements of FOSS, this approach 

provides higher accuracy and higher spatial resolution than other shapesensing systems available. Other methods use cameras to image wing 

deformation; however, these approaches require high-speed processing 

systems, add weight to structures, and are less accurate than the 

FOSS approach. The Armstrong methods can be implemented without 

affecting performance and without the need for structural modifications.

Work to date: The technology has been used to assess large-scale 

composite wings, to evaluate the Global Observer UAV, and in Ikhana 

UAV flight testing, which is believed to be the first flight validation test 

of fiber Bragg grating strain and wing-shape sensing. In eight tests 

that logged 36 flight hours, a total of six fibers (~3,000 strain sensors) 

were installed on Ikhana’s left and right wings. The fiber optic and 

conventional strain gauges showed excellent agreement during multiple 

flight maneuvers. 

Benefits

High spatial resolution: Enables 

measurements approximately every 0.5 

inches

Easy application: Small enough to be 

used on sensitive surfaces without affecting 

performance

Applications

Determining aerial wing shapes

Monitoring turbine blade shapes

Structural health monitoring for bridges, 

buildings, and ships
18 ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014

	


 1(		
%

%	1

	61

7		

Armstrong innovators have developed a highly accurate method for 

measuring liquid levels using optical fibers. Unlike gauges that rely on 

discrete measurements to give broad approximations of liquid levels, 

Armstrong’s novel method provides measurements at 0.25-inch intervals 

within a tank. The system uses FBG sensors located along a single fiber 

optic cable. These sensors actively discern between the liquid and gas 

states along a continuous fiber to pinpoint the liquid level. This significant 

leap forward in precision and accuracy in liquid level sensing offers 

important benefits to many industries. Designed to monitor a rocket’s 

cryogenic fuel levels, the technology can be used in many medical and 

industrial applications.

Work to date: The technology has been demonstrated in multiple 

environments using conventional validation techniques. First, water 

level measurements have been conducted to demonstrate operation 

within a benign environment. Second, liquid level measurements were 

conducted in liquid nitrogen using a 6-foot dewar. Measurements also 

were conducted within a liquid hydrogen environment using a 4-foot 

dewar. The technology performed well in all three cases, demonstrating 

the ability to measure liquid to 0.25 inches. 

Looking ahead: The team continues to push the technology’s fields 

of application, with future tests to determine boundary layers between 

different fluids, such as oil and water. 

Benefits

Precise: Requires just one fiber optic strand 

and one metallic wire

Safe: Is not susceptible to electromagnetic 

interference

Robust: Can be used in corrosive or toxic 

liquids

Applications

Aerospace launch vehicles and satellites

Chemical and refinery plants

Industrial tanks

2%#&	
	
%

An Armstrong research team is advancing a fiber optic sensor that can 

measure strain on structures exposed to temperatures approaching 

1,800 °F, such as reentry vehicles. An initial goal is to provide strain 

data in support of finite element model validation and thermal-structural 

analyses as part of testing in NASA’s Flight Loads Laboratory. That 

research effort is developing sensor attachment techniques for 

structural materials at the small test-specimen level and then applying 

those methods to large-scale hot-structure test articles.

Work to date: The team has performed laboratory tests on control 

surfaces from the X-37 reentry vehicle, characterized the sensor, 

and generated corrections to apply to indicated strains. Substrates 

ranging from metallic super alloys, carbon-carbon, and ceramic matrix 

composites have been tested under combined thermal-mechanical 

loads in both air and inert nitrogen atmospheres.

Looking ahead: The team will examine the use of sapphire-based, 

rather than silica-based, fiber optic interferometry to further increase 

the temperature range towards 3,000 °F. Additional work includes 

ruggedizing the sensor and developing installation methods that would 

lessen the expertise required to attach these sensors.

Benefits

High-temperature sensing: Enables strain 

measurements at much higher temperatures 

than current methods

Unbiased: Does not add localized stiffness

Applications

Reentry vehicles

Jet engines

;
:


Control surfaces during hypersonic flight
ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014 19


	
%		2%#$	$	 

$	

A research team at Armstrong is developing a sensor that can 

measure strain on highly elastic materials, such as inflatable wings, 

reentry vehicles, and airships. Conventional foil strain gauges are 

inaccurate when used on highly elastic materials because of localized 

stiffening due to the relatively high modulus of sensors and their 

adhesive mechanisms, which reduces strain transfer to the sensing 

element. To counteract these problems, the Armstrong team has 

adapted a strain measuring device currently used in the medical field 

to diagnose endothelial dysfunction. 

Work to date: Laboratory testing and sensor calibration has been 

achieved during testing of eight 11- to 17-foot diameter tori from the 

Hypersonic Inflatable Aerodynamic Decelerator (HIAD) vehicle. Under 

compressive loading, strain levels at buckling were determined with 

the data generated from these sensors. 

Looking ahead: The team will continue to characterize and 

evaluate the sensor and flexible adhesive. 

Benefits

Broader range of measurement:

Measures high strains (over 100 percent)

More accurate: Works without creating 

localized stiffening that could bias strain 

measurements 

Applications

Gulfstream III test aircraft

Inflatable wings

Reentry vehicles

Airships

2$#	%		1$%#	
	

This wide-ranging research effort is using FBG sensors and OFDR 

sensing to develop quantitative techniques that can assess damage 

to structural elements. Originally designed to measure strain on UAVs 

and aircraft, this technology provides immediate feedback on strained 

aircraft structures to allow for precise, controlled monitoring to help 

avoid adverse scenarios. Fiber optic sensing with FBGs enables 

sensors to be placed in previously inaccessible regions (e.g., within 

bolted joints), enabling more precise, higher resolution measurements. 

Work to date: Recent work involves mapping fiber optic strain 

measurements into structural health monitoring matrices. A UAV flight 

test validated strain predictions in numerous wingspan locations. 

Additionally, the team designed a system with 24 fibers, 18 of which 

were 40-foot fibers (~17,200 gratings) that instrumented both the left 

and the right UAV wings. Fibers also have been placed onboard the 

small APV-3 UAV and flown with cFOSS. FOSS technology has been 

recently applied to a clamping band that connects two satellite units in 

support of the Magnetospheric Multiscale (MMS) Mission. 

Looking ahead: The team is planning a flight demonstration on 

an Antares launch vehicle in 2016. This effort will provide structural 

information regarding the rocket motor thrust frame as well as 

distributed temperature information along the fuel tanks.

NASA Partner: Kennedy Space Center

Benefits

Smaller and lighter: Offers 100 times the 

number measurements at 1/100 the total 

sensor weight

Safer: Provides validated structural design 

data that enable future launch systems to 

be lighter and more structurally efficient

Multiple modalities: Measures multiple 

parameters in real time

Applications

Aeronautics

Space

Automotive

Civil structures

Wind energy

Industrial processes
20 ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014

	





	1$%#	#


	!%#	'	$		$	'$	

restricted because sonic booms created by shock 

waves disturb people on the ground and can 

%	'	"	
	#	9	$	

			(			$$		(	#		

Federal Aviation Administration (FAA) regulation, innovators 

	O


	#'	(	#%	;				$	

level that is acceptable to both the FAA and the public and 

		#			(		"	%	

cutting-edge testing that builds on previous supersonic 

#	O


		9$%	$;&(		%	

and other strategies that show promise for reducing sonic 

boom levels. 

A variety of factors, from the shape and position of aircraft 

components to the propulsion system’s characteristics, 

determine the make-up of a supersonic aircraft’s sonic 

boom. 


	@		#I			

An Armstrong research effort is focused on demonstrating and validating 

various innovative methods for recording and measuring sonic booms. 

Activities range from collecting data above and below sonic booms 

via a sophisticated array of microphones to gathering information from 

remote sensors and WiFi-controlled microphones strategically placed 

within communities. The team is advancing NASA’s understanding of how 

individuals and communities react to low-noise sonic booms.

Work to date: The team supported the Farfield Investigation of No 

Boom Threshold (FaINT) project and also designed and completed the 

Waveforms and Sonic boom Perception and Response (WSPR) project. 

For the WSPR effort, the team installed WiFi-controlled microphones within 

a 1- to 2-square-mile area on Edwards Air Force Base, then recorded not 

only the low-noise sonic booms but also public reaction to them using 

written and Web-based questionnaires and a smart phone app. 

Looking ahead: Data from the recent community response pilot study 

will be valuable for future public perception studies in communities that do 

not normally experience sonic booms. 

Partners: Participants in the WSPR project included NASA’s Langley 

Research Center; Wyle; Gulfstream Aerospace Corp.; Fidell Associates, 

Inc.; Pennsylvania State University (PSU); and Tetra Tech. Participants in 

the FaINT project included Langley, The Boeing Company, Cessna Aircraft 

Company, Gulfstream, PSU, Wyle, Dassault Aviation, and the Japan 

Aerospace Exploration Agency (JAXA). 

Benefits

Advanced measurement techniques: 


*;

K#\

:



;'']
">+
J
J


J	


recording methods, advanced ground-based 

microphone arrays, airborne sonic boom 

recording systems, and WiFi-controlled 

sensors and microphones.

Expanded polling methods:
;''
:


data collection methods and test protocols 

for future public perception studies.
ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014 21

P	'	
	@	>$	


'	6
@>
7	

CISBoomDA is a real-time, interactive sonic boom display that enables 

pilots to control the location and intensity of sonic booms. The system 

can be integrated into any cockpit or flight control room to help pilots 

place loud booms in specific locations away from populated areas, 

ensure that quiet booms are produced in these areas, or prevent sonic 

booms from occurring at all. This patented technology processes vehicle 

and flight parameters as well as data regarding current atmospheric 

conditions. The prediction data are integrated with a local-area movingmap display that is capable of displaying in real time the aircraft’s 

current sonic boom footprint, enabling pilots to make necessary flight 

adjustments to control them.

Work to date: This proven technology has been operating in Armstrong 

control rooms and simulators since 2000 and has aided several sonic 

boom research projects. 

Looking ahead: The research team is preparing an F/A-18 plane 

for flight testing. The two-seat aircraft will allow “guest pilots” and/or 

passengers from the FAA and avionics firms to observe the CISBoomDa 

technology in action. Also in development is a portable simulation device 

that could be used to demonstrate the technology to avionics firms. A 

solicitation for work on this display was posted in mid 2014 on the NASA 

Solicitation and Proposal Integrated Review and Evaluation System 

(NSPIRES) website.

Benefits

Enables overland supersonic travel: 


#













&
:

J	^
!	%'
>


allow future-generation supersonic aircraft 

to fly over land.

Reduces noise pollution: !	%'


allows for appropriate placement of booms, 

minimizing their effects on the ground.

1$	'%		O	@	

##$	61O7

The FaINT research project is seeking to characterize evanescent waves, 

an acoustic phenomenon occurring at the very edges of the normal 

sonic boom envelope and sounding similar to distant thunder. Certain 

atmospheric conditions and wave refractions create the “shadow 

side” of a sonic boom, where evanescent waves are generated. The 

waves quickly fade and disappear, similar to how boat wakes on water 

decrease with distance. During recent FaINT experiments, researchers 

collected data during a series of low-supersonic, high-altitude flights via 

a 1-mile stretch of microphones along the ground, microphones placed 

more than 2,000 feet above ground, and a microphone on a motorglider 

at altitudes around 10,000 feet. Characterizing the effects of louder and 

quieter sonic booms will help provide data necessary for engineers to 

design future low-boom supersonic aircraft.

Work to date: FaINT provided an extensive database that will be 

mined for a better understanding of shadow-side sonic booms for years 

to come. Currently NASA researchers are analyzing data with a focus on 

defining the acoustic lateral boom cutoff, which is the lateral distance 

beyond which evanescent waves are no longer distinguishable. 

Looking ahead: FaINT will help identify the physical boundaries of the 

sonic boom envelopes of future commercial supersonic aircraft. 

Benefits

Advances sonic boom research: The 

*;
#+	

#+
$J




to help characterize evanescent waves 

and expand knowledge of sonic boom 

propagation effects.

Reduces noise pollution: *;




allow for accurate knowledge of sonic boom 

sound levels.
22 ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014

	


 
	1$%#	#


	@	Q			

6
@Q	7		

Armstrong is continuing a partnership with Aerion Corporation to collect 

flight data about the extent and stability of natural laminar flow (NLF) at 

supersonic speeds. SBLT II consisted of flying a natural laminar flow test 

article beneath NASA’s F-15B research aircraft. The objective is to better 

understand how factors such as Reynolds number and surface roughness 

affect boundary layer transition from laminar to turbulent at supersonic 

speeds. Experiment results can be used to help determine the sensitivity 

of the boundary layer to surface roughness, which can translate into 

manufacturing tolerances for supersonic NLF wing designs.

Work to date: SBLT II collected boundary layer transition data for the 

NLF test article at flight numbers up to Mach 2.0 and chord Reynolds 

numbers in excess of 30 million. Transition data also were obtained for 

surface roughness elements (trip dots, two-dimensional steps) meant 

to replicate disturbances intrinsic to the manufacture and operation of a 

supersonic business jet airplane.

Looking ahead: Additional instrumentation will be added to the 

NLF test article for a second series of flights. The instrumentation will 

allow engineers to obtain additional information, such as the pressure 

distribution over the NLF test article.

Partner: Aerion Corporation designed and built the flight test article, 

and Armstrong provided the ground and flight support.

Benefit

Advances scientific research: Investigates 



J

:
;<*


#
#


over a special test airfoil 


&&
	@P%&	
#$

This research project is using a synthetic schlieren technique to study 

the effects of shock waves on high-speed air travel as part of a larger 

NASA effort to develop a quieter supersonic vehicle. Conventional 

schlieren techniques typically require expensive lighting, mirrors, and 

precise alignment to visualize density gradients and enable shock wave 

visualization. This technology instead uses computer image processing 

technology and a less expensive background-oriented schlieren (BOS) 

technique to visualize shock waves in a wind tunnel. (BOS requires only a 

charge-coupled device [CCD] camera, a light source, and a speckle-type 

background, making it a much simpler and less costly option for flow 

visualization.) This research effort is the first to use a BOS technique to 

visualize supersonic aircraft shock waves in flight. 

Work to date: The team conducted a flight test over the desert using a 

King Air aircraft equipped with a camera and recording an F/A-18 flying 

under it at supersonic speed. Researchers used the results to validate 

the BOS technique.

Looking ahead: The team plans to conduct additional tests with more 

advanced cameras to obtain higher resolution images. The ultimate goal 

of NASA’s shock wave research is to find ways to control shock waves 

and lessen their noise so that it may be possible for supersonic flight to 

become more routine. 

NASA Partner: Ames Research Center

Benefits

Novel: Employs a unique application of a 

technique to understand how shock waves 

affect supersonic vehicles

Advanced: Furthers knowledge and tools in 

;'']




+


#


planes
ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014 23


(	
#$	%%	
	

6


7	

Armstrong researchers are using a schlieren technique to capture 

images of shock waves emanating from aircraft in supersonic flight. 

For supersonic flight to ultimately become acceptable, it is necessary 

to study the shocks and quiet the boom. The ASIS technique captures 

images of shocks by aligning a supersonic aircraft between a cameraequipped aircraft and the sun, and then watching as the shocks put an 

apparent ripple on the sun’s edge. This technique allows for side-view 

imaging at operational altitudes where typical supersonic flights are 

expected to occur. These images will enable researchers to validate data 

from supersonic models and wind tunnel tests. 

Work to date: The team conducted a proof-of-concept demonstration 

of the ASIS technique during a February 2014 flight test and is evaluating 

the results.

Looking ahead: The team will continue to test and mature the 

technology. The sun-ripple concept and aircraft alignment algorithms 

developed for ASIS are being considered for use on future projects. The 

team is working to identify potential research partners.

Benefits

Innovative: Captures side-view images of 

shock waves, as opposed to the top-down or 

mostly bottom-up images captured by other 

techniques

Accurate: Enables precise sonic boom 

estimation by validating supersonic models 

and wind tunnel tests

Researchers collect sonic boom data for the FaINT project.
24 ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014

	




Collision Avoidance Technologies

Researchers at Armstrong are dramatically improving 

upon existing ground collision avoidance technology 

	"	$$	!%#					

leading cause of fatalities in aviation, resulting in roughly 

SUU	#	#			#		
	$"	
$#%#	

warning systems have virtually eliminated this problem for 

large commercial air carriers, the problem still remains for 

%#		#$		%$	'"	


%	'	#'	(	;P%	;#	#	"
"	 

Air Force for more than 25 years to develop automatic col-

$	'	#$%		%#		#	;$	

reduce the risk of ground collisions, the leading cause of 

fatalities in both military and general aviation. The result of 

the collaboration is lifesaving technology that incorporates 

onboard digital terrain mapping data with data-adaptive 

algorithms that predict impending ground collisions.

Global Elevation Data Adaptive 

	
	6B>

7			

Data-adaptive algorithms are the critically enabling technology for 

Armstrong’s GEDACS and automatic collision avoidance system efforts. 

These Armstrong-developed algorithms provide an extensive and 

highly efficient compression capability for global-scale digital terrain 

maps (DTMs) along with a real-time decompression capability to locally 

render map data. These terrain maps and decompression algorithms 

are designed to be easily integrated into an aircraft’s existing onboard 

computing environment or into other mobile embedded environments, 

such as smart phones or tablets, without the need for external data 

download. The GEDACS software package enables developers to create 

maps containing multiple user-defined geographical areas with custom 

fidelities from a variety of data sources. GEDACS provides this ability with 

a single, easy-to-use graphical user interface; simple map definition; and 

data selection procedures. 

Work to date: DTMs created with the GEDACS software have been 

flown and tested on aircraft avionics systems and other mobile embedded 

applications. 

Looking ahead: Maps developed using GEDACS are being considered 

for advanced automotive and space applications that require large areas 

of digital terrain information.

Benefits

Efficient: Provides high compression ratios 

(thousands to 1 for most map requirements) 

Powerful: Integrates and processes more 

than 250 billion separate pieces of terrain 

information into a single decompressed DTM

Highly configurable: Enables users to input 

requirements to create compressed DTMs

Applications

Military and civil aeronautics

Unmanned aerial vehicles
ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014 25

'	B	$$	
'	


	6B

7		
=	

This research project is testing and validating automatic iGCAS 

software technology for use on UAVs in a variety of terrain conditions. 

The technology outperformed engineering expectations in a series 

of demonstration flights using a small, remotely operated integrated 

drone research plane. The team adapted the iGCAS software into an 

application for the AndroidTM smart phone linked to a small Piccolo 

Autopilot. The small drone is an affordable, low-risk, and effective way 

to test the miniaturized iGCAS system before an operational system can 

be installed on a multi-million-dollar unmanned aircraft like Armstrong’s 

Ikhana, which is one of the project’s eventual goals.

Work to date: The project team successfully validated the iGCAS 

software in a series of UAV flight tests on the Dryden Aeronautical Test 

Range. The iGCAS repeatedly executed pull-ups and sharp turns to avoid 

imminent terrain impact and many times extricated the UAV from a box 

canyon. 

Looking ahead: When fully developed and matured, the miniaturized 

iGCAS technology could have wide applications for potential use in 

general aviation aircraft, including crewed and remotely/autonomously 

operated unmanned aircraft systems. In 2014 the research team intends 

to incorporate obstacle avoidance and a specialized pilot interface for 

general aviation use.

Android is a trademark of Google Inc.

Benefits

Increases safety: Provides the framework 

for analytical systems that can learn, 

predict, and adapt to both routine and 

emergency situations

Portable and affordable: Enables 

implementation on existing aircraft systems 

and on tablets and smart phones

Applications

UAVs (navigation and research) 

Military and civil aeronautics (collision 

avoidance, aerial firefighting, crop dusting)

$&Q'$	
	$%	 


	6
7

Effective multi-level autonomous piloting systems require integration 

with safety-critical functions. The MAPS project seeks to develop 

a hierarchal autonomous system framework that will depend on 

deterministic systems with higher authority to protect against 

catastrophic piloting faults and allow a lower level certification for the 

machine learning sub-systems. The multi-layered approach provides the 

framework for analytical systems that can learn, predict, and adapt to 

both routine and emergency situations. 

Work to date: The hierarchical decision chain and framework, 

hardware, and embedded processing related to ground collision 

avoidance is in place for a sub-scale platform. Flight tests on a quadrotor model helicopter demonstrated successful limitation of flight 

decisions when facing imminent ground collision. 

Looking ahead: The team is developing a full set of safety-critical 

functions for the sub-scale platforms and working to scale up to larger 

UAVs. 

Partners: University of California at Berkeley and Stanford University 

are developing algorithms, and the FAA is participating in the 

certification process.

Benefits

Increases safety: Integration of safetycritical functions improves outcomes in 

emergency situations.

Certifiable: Removal of safety-critical 

functions from the autonomous control 

enables adaptable processes to be certified 

to a lower level.

Applications

UAVs and unmanned submersibles

Autonomous rail transport

Deep space exploration

Driverless vehicles
26 ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014

	





'			#$%

Armstrong innovators design and integrate data 

acquisition systems for research, support, and 

&&&P	$"				#	

systems leverage commercial off-the-shelf parts to keep 

costs low and ease integration with legacy systems. At the 

		#	%&%				%	

''	;		$		$$		$	(	$	

	!9($	%	$$	"	

Designed for aerospace applications, many of these 

'		(					'	

		;#		)		$	#		

manufacturing operations, business processes, and energy 

management, to name a few.

Platform Precision Autopilot (PPA) 

Armstrong innovators have developed a flight control system that allows 

an aircraft to maintain an attitude and heading within 5 meters of a desired 

position. The PPA is a digital system that augments the legacy analog 

Gulfstream III (G-III) autopilot system. The PPA consists of an embedded 

microcontroller-based flight computer and navigation algorithms that 

use externally provided attitude and differential GPS information to 

generate aircraft control commands. The system features a unique use of 

a controller area network (CAN) system and design interface to imitate an 

instrument landing system (ILS) and enable precise repeat-pass flights. 

This proven technology has been flying on Armstrong’s G-III aircraft for 

more than 5 years.

Work to date: The technology was developed for NASA’s Uninhabited 

Aerial Vehicle Synthetic Aperture Radar (UAVSAR) program to aid in 

precise repeat-pass scientific missions. The PPA enables the G-III aircraft 

to perform missions that are more complex and demanding than ever.

Looking ahead: The team is working to establish an F/A-18 interface for 

pilot pitch queuing in support of launch vehicle adaptive control research. 

A potential NASA application is the Stratospheric Observatory for Infrared 

Astronomy (SOFIA) mission, where the PPA would provide precision 

automated heading control. Additionally, the PPA is being revised to 

support the Coordinated Trajectories project by hosting a peak-seeking 

control algorithm. 

Benefits

Precise navigation: Controls an aircraft 

within a specified tolerance

Compact and low power: Measures 3x5 

inches and operates at less than 5 watts

Applications

Scientific and military surveillance

Terrain mapping
ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014 27


	>	
'$$	

@	6
>
&@7	
			


$	
;	

Armstrong innovators have developed an ADS-B system for unmanned 

aerial vehicles. The system relies on highly accurate GPS signals to 

provide increased situational awareness and a self-separation assurance 

system to avoid accidents. This state-of-the-art technology automatically 

broadcasts a UAV’s exact position 120 miles in every direction every 1 

second, as opposed to legacy radar-based transponder systems that 

“sweep” for position every 12 seconds. Accurate to within 5.7 feet, 

this Armstrong-developed technology integrates commercial ADS-B 

hardware, radio data-link communications, software algorithms for 

real-time conflict detecting and alerting, and a display that employs 

a geobrowser for three-dimensional graphical representations. Some 

manned aircraft already have adopted ADS-B technology. The Armstrong 

team is the first to apply the system architecture to UAVs.

Work to date: In 2012, the team developed, demonstrated, and 

validated an ADS-B system integrated into an unmanned aircraft system 

for increased situational awareness and self-separation assurance. 

Looking ahead: The team is working to refine the sense-and-avoid 

algorithm’s conflict detection, trajectory estimation, and prediction 

capabilities for self-separation assurance. 

Benefits

Improves safety: Enhances sense-andavoid capabilities to maintain self-separation 

for UAVs

Highly accurate and fast: Provides 

location data that are accurate to within 5.7 

feet every 1 second 

Applications

Military missions 

and training 

Law enforcement 


$


Scientific research

>(	
$	
%	 

and Control

Armstrong researchers are investigating ways to increase aircraft 

maneuverability, safety, and fuel efficiency by applying networks of 

smart sensors distributed across an aircraft. This “fly-by-feel” concept 

could enable a vehicle to autonomously react to changes in aerodynamic 

and structural conditions. Distributed pliable membrane sensors obtain 

real-time information and convert it into aerodynamic information that 

can be used for adaptive flight control. In comparison with conventional 

sensing technologies, which measure aerodynamic parameters from 

only an aircraft’s fuselage, these smart sensors enable localized 

measurements at nearly any surface on an aircraft structure. The 

ultimate goal is to feed real-time sensor information into a control 

scheme such that the aircraft can autonomously control the position 

of a surface appropriately for active aeroelastic wing control.

Work to date: The team has conducted sensing and analysis work with 

hot-film sensors installed on Gulfstream III, F/A-18, and X-56A aircraft. 

Looking ahead: Next steps involve more investigative work with the 

X-56 aircraft, specifically hot-film sensors combined with fiber optic 

strain sensing and associated data fusion algorithms to address 

distributed sensing and control applications.

Partners: Texas A&M University, California Institute of Technology, 

Illinois Institute of Technology, University of Minnesota, Air Force 

Material Command, Air Force Research Laboratory, and Tao Systems, Inc.

Benefits

High-performance: Offers certifiable 

performance and stability guarantees and 

aerostructural efficiency

Improved safety: Provides localized data, 

enabling engineers to be more confident that 

design specifications offer appropriate safety 

margins

Applications

Aircraft testing and design

Improved drag reduction and increased lift 

performance

Active aeroelastic control of flexible structures
28 ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014

	


 
'			#$%

($	>	
I	
	6>
7	

Armstrong researchers have developed a PDAT that can be easily 

transported to and set up at remote locations to display and archive data 

in real time. The PDAT was developed to collect data from strain gauges 

and fiber optic sensors installed on a revolutionary wing flap while it was 

being constructed by NASA partner FlexSys Inc. in Ann Arbor, Michigan, 

as part of the Adaptive Compliant Trailing Edge (ACTE) project. The PDAT 

enabled the Armstrong team to monitor and analyze data during the 

construction process and provide vital feedback to designers on site at 

FlexSys instead of having to wait until construction was completed and 

shipped to Armstrong’s facility. 

Work to date: This unique and flexible system has 64 channels for 

analog data, 32 channels for thermocouples, and 6,000 parameters of 

fiber optic data. It is currently configured to gather strain gauge and 

thermocouple inputs, but a variety of other hardware can be installed, 

including cards for pressure transducers, voltages, currents, motion 

packs, accelerometers, MIL-STD-1553 and ARINC 429 aircraft data buses, 

and Ethernet packets.

Looking ahead: The PDAT has been an integral part of the ACTE project 

and is versatile enough to become a successful component of many 

current and future Armstrong projects.

Benefits

Convenient: This innovation enables realtime analysis of data collected at remote 

locations.

Portable: The hardware is easily removable, 

attaches to a single heat-sink pallet, and fits 

into a single small case for quick transport. It 

can be used in a variety of locations, including 

laboratory, hangar, and flight line. 

Flexible: The technology can be quickly 

reprogrammed to support various tests, and 

it can display and archive data from virtual 

streams.

O;P	

Armstrong researchers have developed a networked instrumentation 

system that connects modern experimental payloads to existing analog 

and digital communications infrastructures. In airborne applications, this 

system enables a cost-effective, long-range, line-of-sight network link over 

the S and L frequency bands that support data rates up to 10 megabits 

per second (Mbps) and a practically unlimited number of independent 

data streams. The resulting real-time payload link allows researchers to 

make in-flight adjustments to experimental parameters, increasing overall 

data quality and eliminating the need to repeat flights.

Work to date: The team has developed and flight-tested the 10 Mbps 

bidirectional aircraft-to-ground line-of-sight network. A follow-on project, 

Space-Based Range Demonstration and Certification (SBRDC) Flight 

Demonstration #2, involved integration of this system with a phasedarray antenna and controller to provide a 10-Mbps over-the-horizon 

network downlink. This prototype system was further refined into a more 

operational system that provided the Airborne Research Test System 

(ARTS) aboard the Full-Scale Advanced Systems Testbed (FAST) access 

to thousands of parameters from the heavily instrumented aircraft. 

Engineers were able to view ARTS network data output in the control 

room, without replacing any aircraft instrumentation or ground equipment. 

Looking ahead: Work has begun to design a new system that 

incorporates state-of-the-art transceiver technology. The new system is 

expected to significantly increase throughput up to 40 Mbps.

Benefits

Flexible: Expands the utility of 

existing airborne platforms with legacy 

communications systems by supporting 

state-of-the-art payloads that leverage current 

network technology

Economical: Achieves a bidirectional lineof-sight network without the need to replace 

existing communications infrastructure

Flight efficient: Reduces the need for 

repeat flights by offering real-time control of 

experimental parameters
29

Airborne Research Test System, 

Fourth Generation (ARTS IV) 

ARTS IV is a hardware and software platform for testing advanced 

control and sensor concepts on Armstrong’s Full-Scale Advanced 

Systems Testbed (FAST). ARTS IV reduces the effort and cost of flight 

testing research by providing a robust, flexible, reconfigurable computing 

platform for hosting research experiments. The software architecture 

of ARTS IV provides the ability to host multiple research experiments 

simultaneously and allows researchers to reconfigure the software to 

meet various mission needs. 

Work to date: The ARTS platform has been used to investigate a 

number of ground-breaking control technologies with potential to 

revolutionize how air and space vehicles are controlled and how human 

operators interact with them. Specifically, the benefits of simple adaptive 

control architectures have been explored for improving the robustness 

and safety of commercial aircraft. 

Looking ahead: Current research is focused on enabling lighter weight 

structures and addressing one of the boundaries to a number of novel 

control approaches through the use of structural load feedback within an 

optimal control architecture. 

Partner: ARTS IV was developed in collaboration with the West Virginia 

High Technology Consortium Foundation.

Benefits

Flexible: Provides an array of options to test 

and implement advanced control concepts

Configurable: Can be quickly customized 

for various experiments

Partitioned: Separates research 

experiments from the core system, allowing 

research to be changed without re-performing 

formal testing of the core ARTS IV software

Applications

Validating new flight control concepts

Expanding aircraft envelope

Testing aircraft limits

Next-Generation Post-Flight Processing 

and Analysis with Data Mining Toolset

Aircraft flight test projects generate large amounts of data. One complex 

vehicle flight typically generates several hundred megabytes of data. A 

single project could involve several hundred flights, and a dozen active 

projects could be in progress at a major research center, requiring the 

management of terabytes of data. Armstrong researchers are testing 

the OMEGA Data Environment (ODE) software tool from Smartronix® to 

achieve rapid access to specific types of data. This commercial off-theshelf (COTS) data mining tool is allowing researchers to find needles in 

haystacks, or bits within terabytes.

Work to date: Armstrong researchers have applied the ODE tool 

to identify anomalies on C-17 air data computers. The ODE software 

enabled the team to search a 25-dimensional space within minutes, an 

exercise that otherwise would have taken a prohibitive amount of time to 

accomplish. 

Looking ahead: Researchers are continuing to test and evaluate the 

ODE data mining tool for possible use at all NASA Centers. They will also 

be examining near-real-time publishing, in conjunction with the OMGEA 

NExT software. The NExT tool creates graphic displays in real time, 

based on input telemetry data. The displays are configured with open 

source *.xaml files; streaming data are recorded in industry standard 

*.CH10 files and “published” (i.e., converted into customary engineering 

and desktop formats suitable for documentation).

Benefits

Fast: Allows practical searching through 

terabytes of post-flight data 

Easy to use: Permits rapid data searches by 

inspection via its visualization feature 

Applications

Post-flight data analysis

Records management

Smartronix is a registered trademark of Smartronix, Inc.

ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014
30 ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014

	




2		
	#$%

A P	(^'		#	#		O


			

develop methods and tools that adequately model 

fundamental physics and allow credible physics-

(	)			$	#	'#$	

systems. Research focuses on solving some of the most 

$	#$$%		#	!%#		
%	

innovators are contributing to this research in several ways:

_	 Exploring adaptive guidance systems that could detect 

conditions likely to result in dangerous situations and 

automate compensating maneuvers

_	 $%	#%#&$	'		'	!%#	

planning designs for high-speed vehicles

_	 Designing high-temperature insulative and advanced 

composite materials 

This research will enable the development of highly reliable 

		#	"

Air Launch from a Towed Glider 

This research effort is exploring the concept of launching a rocket from 

a glider that is towed by an aircraft. The idea is to build a relatively 

inexpensive remotely piloted glider that could be towed to altitude by a 

large transport aircraft. The glider would carry a booster rocket capable 

of launching payloads into orbit. After the rocket launch, the glider would 

return independently of the tow aircraft to its base to be used again. This 

approach could significantly reduce the cost and improve the efficiency of 

sending satellites into orbit. 

Work to date: Three separate technical feasibility studies completed by 

independent contractors indicate the technique could achieve significant 

performance gains over vertical ground launches of similar-sized rockets. 

The Armstrong team has designed and is building a sub-scale research 

model to test operational aspects and characterize flight performance and 

handling qualities. Flight testing and crew training have begun on a single 

fuselage glider that will be towed to altitude. 

Looking ahead: Future plans involve continuing work to assemble a 

one-third scale glider model with a 24-foot wingspan to obtain operational 

experience while under towed flight as well as performance and handling 

qualities data. Plans are underway to flight demonstrate a rocket launch 

from the sub-scale model. 

Partner: Whittinghill Aerospace is fabricating a rocket for this air launch 

flight demonstration, under a Phase III SBIR.

Benefits

More economical: Use of a simple remotely 

piloted glider, without the complex propulsion 

and crew life support systems required for 

a crewed, powered aircraft, provides an 

inexpensive air-launch platform.

Increased payload: A towed glider can 

carry more than twice the payload of a 

dedicated powered aircraft.

Safer: Remotely piloted gliders that are 

towed 1,000+ feet behind the tow plane offer 

a substantial safety perimeter from the highenergy systems inherent in rocket boosters (as 

compared to other air-launch methodologies).
ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014 31


$	%	O))$	6
O7	

The primary objective of the ACN project is to advance the technology 

readiness level (TRL) of the dual-bell rocket nozzle through flight testing 

and research. This nozzle is predicted to outperform the conventional 

bell rocket nozzle, which is inefficient at any altitude other than its design 

altitude. With a distinct dual-bell shape, this nozzle can be optimized 

for both low and high altitudes. As a result, the nozzle plume is never 

significantly over- or under-expanded, yielding a higher propulsive 

efficiency. When considering a rocket’s performance over its entire 

integrated trajectory, the dual-bell nozzle is predicted to achieve a higher 

total impulse, allowing for the delivery of greater mass payloads to low 

Earth orbit (LEO). The current effort is focused on preparing for dual-bell 

rocket nozzle operation during captive-carried flight with a NASA F-15, 

enabling the performance benefits with the dual-bell rocket nozzle to be 

quantified in a relevant flight environment. 

Work to date: Progress to date has primarily focused on: (1) the 

development of the conceptual design, including integration with the F-15 

flight testbed; (2) the construction of a concept of operations plan; and (3) 

an initial definition of all top-level objectives and requirements. 

Looking ahead: An ambitious 5-year plan includes a framework for 

design, analysis, ground testing, and flight testing. 

NASA Partner: Marshall Space Flight Center

Benefits

Economical: The dual-bell nozzle is 

predicted to increase the delivery of payload 

mass to LEO by up to 5 percent, and may 

reduce the cost of delivering payloads to 

LEO.

Increased rocket engine structural 

integrity: Low-altitude nozzle flow will not 

be significantly over-expanded, which may 

lead to increased uniformity, symmetry, and 

stability of the nozzle plume flow field.


'	$	#		 

Hypersonic Vehicles

This research effort aims to develop software control algorithms that 

will correct for roll reversal before it happens. Roll reversal occurs 

when an aircraft is steered in one direction but rolls the opposite 

way due to aerodynamic conditions. The problem often compounds 

as a pilot attempts to correct for the motion by over-steering in the 

original direction, leading to uncontrollable roll. Unexpected yaw and 

subsequent roll reversal has caused the loss of high-speed, lifting 

body–like vehicles. The team has employed novel predictive software 

within adaptive controller technology to detect conditions likely to result 

in aircraft roll reversal and then automate compensating maneuvers to 

avoid catastrophic loss. 

Work to date: University of Michigan’s retrospective cost model 

refinement (RCMR) control algorithm has been integrated into a flight 

simulator and tested with prerecorded, open-source parameter data, 

which replicates the roll reversal anomaly. 

Looking ahead: Next steps involve upgrading the RCMR code to 

account for a six-degree-of-simulation environment (forward/back, up/

down, left/right, pitch, yaw, and roll) with eventual application in a flight 

test environment.

Partners: University of Michigan, other government research agencies, 

and aerospace firms.

Benefits

Operates independently: Unlike other 

standard control systems, this method allows 

for compensation and control of aircraft roll 

reversal without a priori knowledge of the 

dynamics. 

Improves safety: This technology is 

expected to prevent crashes that occur due 

to uncontrolled roll.

Increases envelope: RCMR would enable 

planes to travel safely over a larger envelope.

Applications

Hypersonic jets

Lifting body–type space vehicles and reentry 

vehicles
32 ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014

	


 2		
	#$%

Adaptive Guidance Algorithms for 

Hypersonics 

This research effort is exploring the development of an adaptive guidance 

system for hypersonic vehicles. Traditionally, guidance is preprogrammed 

before flight both for manned and unmanned hypersonic vehicles. 

However, this offline, preprogrammed approach is not optimal in the 

event of unexpected situations, such as aircraft aerodynamic shape 

changes or thermal constraints. An adaptive guidance system would 

include predictive algorithms that could detect conditions likely to result 

in dangerous situations and automate compensating maneuvers to avoid 

catastrophic loss. 

Work to date: Guidance and control algorithms have been tested in a 

simulator.

Partner: The Defense Advanced Research Projects Agency (DARPA) 

provided funding for this project.

Benefits

Improves safety: An adaptive system could 

detect and compensate for unsafe and/or 

unexpected situations/environments. 

Increases envelope: The system would 

enable aircraft to travel safely over a larger 

envelope.

Fuel efficient: The system would adapt to 

changing conditions to maintain the most fuel 

efficient flight.

Applications

Hypersonic jets

General aviation aircraft

High-Altitude Atmospheric Reconstruction

Armstrong researchers are participating in an ongoing effort to model 

high-altitude atmospheric environments in order to improve flight 

planning designs for high-speed vehicles. The primary atmospheric 

conditions of interest in the upper stratosphere and lower mesosphere 

include air density, temperatures, winds, pressure, and expected 

uncertainties. These conditions must be characterized and understood 

in order to ensure the safety of high-speed aircraft and the people 

inside them. Reliable upper atmospheric models contribute to better 

flight parameter choices for speed and altitude and enable faster, safer, 

and higher flights for ultra high-speed vehicles. 

Work to date: Armstrong provided an atmospheric reconstruction 

of the flight regime or best-estimate atmosphere (BEA) for NASA’s 

Hyper-X scramjet demonstrator, DARPA’s Hypersonic Technology 

Vehicle 2, the U.S. Army’s Advanced Hypersonic Weapon launched 

glider, and the U.S. Air Force’s X-51 hypersonic scramjet. Each of these 

projects has enabled the team to refine modeling and data collection 

capabilities. 

Looking ahead: The team is currently working on several projects: 

(1) detecting and mitigating atmospheric turbulence to improve aviation 

travel, (2) modeling the effects of radiation on pilots, (3) investigating 

how cosmic energies are affecting the atmosphere, and (4) developing 

sensors for in situ atmospheric measurements and transmitting these 

data to appropriate users.

Benefits

Increased efficiency: Contributes to 

understanding of key parameters for ultra-high 

altitudes 

Improved safety: Helps designers and 

planners reduce risks associated with 

atmospheric reentry and radiation exposure

Applications

High-speed aircraft test flight research

Weather prediction and climate change 

research

Global Positioning System (GPS) performance 

research 
ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014 33


$$	%	#$	 

	
	6
7		

An Armstrong research team has combined high-temperature insulative 

and advanced composite materials in a unique design to protect 

aerospace vehicles from both the high aerodynamic loads as well as 

high temperatures generated by reentry from space. This dual-purpose 

sandwich panel design carries both thermal and mechanical loads and 

increases the operational efficiency of hypersonic vehicle aeroshells. 

Conventional multi-use hypersonic vehicles typically use non-loadbearing insulation systems to thermally protect the vehicle while using an 

internal skeleton to bear the mechanical loads. The Armstrong-developed 

SITPS offers a combined advanced thermal protection system that is 

both structurally and volumetrically efficient. It uses high-temperature, 

ceramic-matrix composite and lightweight insulation materials. 

Incorporating the insulation within a more robust sandwich panel could 

significantly reduce the operational costs for preparing a vehicle for its 

next mission.

Work to date: The team developed the materials and process to 

fabricate a 20x36-inch concept panel for a specific core design and 

mechanically tested it in a laboratory using three separate methods. 

The team also has developed a material database of SITPS strength 

and thermal performance characteristics. In addition, the team examined 

alternate sandwich core designs to increase the overall thermal and 

mechanical performance of the concept panels.

Looking ahead: Next steps involve developing panel closeouts and 

panel-to-panel joints in addition to manufacturing curved SITPS panels.

NASA partners: Langley Research Center and Glenn Research Center

Benefits

Robust: Increases durability of the TPS, 

thereby decreasing maintenance time

Strong: Offers higher structural efficiency

Efficient: Permits the reduction of vehicle 

mass with its combination of thermal and 

load-bearing capabilities 

Applications

Multi-use hypersonic vehicles 

Aircraft exhaust-washed structures

Technicians prepare a Pegasus rocket booster 

for flight tests with the X-43A “Hypersonic 

Experimental Vehicle,” or “Hyper-X.”
34 ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014

	




Efficient Aerospace Vehicle Technologies



%							P	 

%$		#			O


	"	 

Armstrong researchers are constantly striving to 

($			$$	#		!%#	^	#%#	

development, fabrication, and operations processes. 

From a new wing design that could exponentially 

	$					'$			 

for single-engine electric aircraft, our researchers are 

%	I	$	#		"	


O>Q&>	
(&
$	B$			

Armstrong researchers are experimenting with a new wing shape 

that could significantly increase aircraft efficiency. The team has built 

upon the research of the German engineer Ludwig Prandtl to design 

and validate a scale model of a non-elliptical wing that reduces drag 

and increases efficiency. The approach to handling adverse yaw 

employs fine wing adjustments rather than an aircraft’s vertical tail. The 

Preliminary Research Aerodynamic Design To Lower Drag (PRANDTL-D) 

wing addresses integrated bending moments and lift to achieve an 

11 percent drag reduction. In a propeller application, efficiency could 

increase by 13 percent. 

Work to date: In 2013, the team developed, demonstrated, and 

validated a scale model of an improved PRANDTL-D wing. Initial results 

from a 4-month, small-scale flight experiment unequivocally established 

proverse yaw. Additionally, preliminary results of the parameter 

estimation show the correct sign and comparable magnitude to the 

analysis. 

Looking ahead: Next steps are to build and test a propeller with the 

PRANDTL-D configuration.

Benefits

Highly efficient: Increases total aircraft 

efficiency by as much as 62 percent, including 

efficiency increases in the areas of wing (12.5 

percent), drag reduction (25 percent), and use 

in propulsion systems (13 percent)

Quieter: Decreases noise

Faster: Allows aircraft to fly faster

Applications

Aircraft

Turbines

Energy delivery systems
ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014 35

Turbo-Electric Distributed Propulsion 

	
	

An Armstrong team is developing a static test stand for single-engine 

electric aircrafts. Researchers will use this technology to identify ways 

to measure motor and battery efficiencies; evaluate multidisciplinary 

dependencies; and provide insights into propeller, motor, and electronics 

designs specific to electric aircraft propulsion. The ultimate goal of the 

project is to determine a standardized way to measure electric engine 

efficiencies. 

Work to date: In 2013, the team began constructing the test stand and 

researching electric propulsion test motors. Small-scale versions of the 

stand were also designed and built to demonstrate the effectiveness of 

test sensor installation techniques and measurement technology required 

for the full-scale design.

Looking ahead: The group will complete construction and static testing 

and mount the stand on a truck for dynamic testing. A ground testbed 

for performance and control characteristics will be used to evaluate 

new electric propulsion technologies that could be applied to vehicle 

integration. This research has already spawned interest in a follow-on 

proposal from NASA’s Hybrid Electric Integrated System Testbed (HEIST) 

project, which is investigating power management and distribution for 

hybrid electric propulsion systems.

Benefits

Improves measurement: Standardizes 

measurement of electric engine efficiencies

Novel: Implements sensors in a unique way 

to enable testing configurations

Applications

Electric aircraft engines, generators, 

controllers, and batteries

Research for novel types of energy 

storage systems

Electromagnetic Flow Control to Enable 

O$	Q	1$;	M%

A research team has developed a solid-state electromagnetic device 

that, when embedded along the leading edge of an aircraft wing, can 

disrupt laminar air flow on command. The methodology employs a 

combination of high-voltage alternating and direct current electric fields 

and high-strength magnets to generate cross flow. This cross flow either 

forms vortices or trips the flow to turbulent (depending on conditions), 

energizing the boundary layer to keep the flow attached and prevent 

stall. Presumed usage would be for an aircraft to activate the device at 

takeoff, turn the device off after gear-up and initial climb-out, then turn it 

back on for descent and landing. Using natural laminar flow principles in 

aircraft design can reduce fuel burn by 6 to 12 percent.

Work to date: The device has been tested on a flat plate in a wind 

tunnel. 

Looking ahead: The group plans to test the device on a remotely 

operated integrated drone aircraft and is targeting 2015 for tests on a 

Prototype Technology Evaluation Research Aircraft (PTERA). 

Partner: Brigham Young University provides a wind tunnel and 

machining facilities to build test articles.

Benefits

Efficient: Enables fuel reduction

Simple: Works with no moving parts, 

simplifying fabrication and maintenance

Improves safety: Facilitates safer takeoffs 

and landings

Applications

Aircraft wings

Industrial fluid processing

Heat transfer processes
36 ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014

	


 	
	=#$	#$%

	$%		

Military aviation relies on aerial refueling to conduct numerous combat, 

reconnaissance, and transport missions. Increasingly, unmanned aircraft 

are conducting these types of missions, yet they are not designed for 

in-flight refueling. Armstrong researchers have developed a system that 

allows two UAVs to fly in formation so that refueling can occur. The system 

consists of an image processing and control system on the receiving UAV 

that syncs with the GPS on the tanker UAV to enable formation flight. 

Subsequently, the image processing system collects azimuth, elevation, 

and range information so that the control system can provide commands 

to link the two aircraft and UAV-to-UAV refueling can commence. This 

research is part of NASA’s Autonomous Aerial Refueling Demonstration 

(AARD) effort.

Work to date: The technology performed successfully in flight tests 

with manned aircrafts operating as surrogate UAVs (an F/A-18 and a 

KC-707 tanker). The initial Phase 1 test used manned aircraft operating 

with an automated flight control system and demonstrated two out of six 

successful refueling attempts. Phase 2 improved on this “plug success 

ratio” and tested different configurations, such as evaluating different sun 

angles to the optical tracker and engaging in a turn.

Looking ahead: Next steps involve flight tests with unmanned aircraft. 

The team is looking for an industry partner to further development efforts.

Partner: Sierra Nevada Corporation

Benefits

Stable: Offers excellent relative 

station-keeping capabilities

Accurate: Cues the receiving UAV aircraft 

to the position of the tanker UAV

Safe: Reliably retreats in a controlled and 

predictable manner to prevent contact in 

instances of declared “misses”

Applications

UAV refueling

Automated manned aircraft refueling

Formation flight


&&
	
=	
$	$%

Armstrong researchers collaborated in an effort that successfully 

demonstrated autonomous aerial refueling between two unmanned, 

high-altitude aircraft. Two Global Hawk UAVs, one outfitted as a 

receiver and the other as a tanker, flew a series of demonstration 

flights to validate advanced UAV-to-UAV aerial refueling control system 

technology. The two aircraft successfully flew for the first time as close 

as 30 feet in formation. The aircraft rendezvoused and flew for more 

than 2.5 hours under autonomous formation control, the majority of time 

within 100 feet of each other. This research effort (referred to as the 

KQ-X project), is a follow-on to NASA’s AARD project, in which manned 

aircraft operating on autopilot functioned as surrogate UAVs to test flight 

control and optical tracking systems.

Work to date: The demonstration flights occurred between January 

and May 2012 and achieved many milestones. The lead receiver aircraft 

completed all planned tests to validate the associated program hardware 

and software. The trailing tanker aircraft successfully demonstrated 

precision control in formation with manual and automated breakaway 

maneuvers.

Looking ahead: Next steps involve further tests with unmanned 

aircraft. The team is looking for an industry partner to advance these 

development efforts.

Partners: DARPA, Northrop Grumman Corp., and Sierra Nevada 

Corporation

Benefits

In-flight refueling: Allows UAVs to fulfill 

longer missions with longer flights

Increased mission scope: Permits more 

flexibility in UAV use

Long-term station keeping: Reduces the 

number of takeoffs and landings to fulfill a 

given mission

Automated refueling: Relieves pilots of 

burdensome flight refueling missions

Applications

UAV refueling

Automated manned aircraft refueling

Formation flight
ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014 37

Data Fusion to Estimate Vortex Location 

for Drag Reduction in Formation Flight 

NASA is investigating the potential benefits of flying aircraft in the 

aerodynamic wake vortex emanating from a lead aircraft’s wing tip. 

Analytic studies predict that a trailing aircraft in the updraft portion of 

a wake vortex may experience drag reductions of 15 percent or more 

by gaining additional lift. One of the technical challenges is finding the 

optimal position within the vortex to fly. This Armstrong research project 

is evaluating a methodology that fuses data from existing sensors to 

estimate the optimal position. 

Work to date: A proof-of-concept simulation has demonstrated 

improvement in vortex estimation when combining data from the 

aircraft’s moment and fuel flow sensors.

Looking ahead: Near-term work involves building software to 

perform data fusion with real-time measurements. Longer-term goals 

are to evaluate the approach on an actual flight test and then a live 

demonstration of formation flight for drag reduction and fuel savings.

Benefits

Improves accuracy: In simulations, data 

fusion of moment and fuel flow sensors more 

accurately estimates the vortex core than do 

data from the individual sensors.

Increases efficiency: Improved accuracy 

will result in greater drag reduction and fuel 

savings.

Applications

Military formation flying

Commercial formation flying

UAV swarming

)	Q		
	 

1	1$%#	6Q
117

Experimental in-flight evaluations have demonstrated that the concept 

of formation flight can reduce fuel consumption of trailing aircraft by 

10 percent. Armstrong researchers have developed a peak-seeking 

control algorithm that can increase this efficiency by another 2 percent. 

The innovation works by optimizing, in real time, the lift distribution 

across the wing of an airplane flying within the wingtip vortex of another 

airplane. Conventional trim schedules use anti-symmetric aileron 

deflections to counter roll asymmetries and keep the wings level. In 

formation flight, however, this approach can “dump” lift near the wingtip 

where the vortex effects are greatest, reducing the amount of benefit 

gained. The peak-seeking solution instead uses all available control 

surfaces across the span of the wing to find the best solution to maintain 

trimmed flight within the vortex.

Work to date: The research team has developed a simulation that 

includes probabilistic models of the wind-drift and descent of aircraft 

wakes, the aerodynamic interference effects of wingtip vortices on other 

aircraft, and formation guidance and control laws. 

Looking ahead: The group is developing a flight experiment to 

demonstrate drag reduction through cooperative trajectories using 

commercial, off-the-shelf avionics systems, including Automatic 

Dependent Surveillance Broadcast (ADS-B) data link technology. The 

experiment is expected to fly in 2015. 

Benefits

Efficient: Improves fuel savings in formation 

flight by an additional 2 percent

Economical: Achieves objectives with 

existing control surfaces

Saves time: Allows airplanes to fly closer 

together, reducing airspace congestion

Applications

Commercial passenger and cargo aircraft 

Military aircraft

Drone aircraft
38 ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014

	


 Efficient Aerospace Vehicle Technologies 	
	=#$	#$%

P&
P%	$			 

)		

Innovators have developed a peak-seeking algorithm that can reduce 

drag and improve performance and fuel efficiency by optimizing aircraft 

trim in real time. The algorithm determines a unique trim position for 

an aircraft by employing a time-varying Kalman filter to estimate the 

gradient of a performance function using in-flight measurements. 

Existing trim control systems preprogram position data into an aircraft’s 

computer, based on knowledge gained from test flights and wind tunnel 

experiments. In contrast, this innovation determines in real time the 

most fuel-efficient trim surface position by taking into account actual 

flight conditions and an aircraft’s physical condition. This customized 

approach results in maximum fuel efficiency for each particular aircraft.

Work to date: The Armstrong team has validated the algorithm with a 

series of F/A-18 experiments. 

Looking ahead: Future flight research efforts will work to further 

mature the technology and transition it to other aircraft. For example, 

the team is currently working with the U.S. Navy to study the potential 

benefits and costs of implementing the technology on the F/A-18 E/F 

military aircraft. 

Benefits

Efficient: Reduces fuel consumption and 

extends the operating range of aircraft

Fast: Determines and maintains the optimum 

trim surface position solution within 5 minutes, 

despite disturbances and other noise

Customized: Determines unique trim position 

using in-flight measurements

Variable: Works on multiple effectors in 

multiple axes simultaneously 

Applications

Military jets and commercial airlines

The payload operations room of the Global Hawk Operations Center at NASA’s 

Armstrong Flight Research Center is staffed for a taxi test. Researchers monitor 

data from their instruments on the screens in the foreground, while pilots and 

engineers monitor aircraft operation in the room ahead of the partition. 
ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014 39

	




Low-Carbon Propulsion Technology

#	2&N4	B		;$$	$P	$P	#	;#		!	(#	

O


<	>&`				#	%		


		!%#		NUSz"

Alternative Fuels’ Effects on Contrails 

			6


7	1$%#	

Experiment

Armstrong’s flight expertise and airspace are being leveraged to 

support a series of tests that will study the effects of alternate biofuel 

on engine performance, emissions, and aircraft-generated contrails 

at altitude. Sponsored by NASA’s Langley Research Center, the 

ACCESS-II flight experiment involves flying a DC-8 aircraft as high 

as 38,000 feet while three instrumented aircraft—a Langley HU-25C 

Guardian, a Falcon from the German Aerospace Center (DLR), and a 

T-33 from the National Research Council of Canada (NRC)—trail behind 

at distances ranging from 300 feet to more than 10 miles and measure 

exhaust fumes from the DC-8 engines. During the flights, the DC-8 

engines will be powered by conventional fuel and a blend of two other 

mixes of conventional fuel and an alternative biofuel. More than a dozen 

instruments will characterize the soot and gases collected from the 

DC-8, monitor the way exhaust plumes change in composition as 

they mix with air, and investigate the role emissions play in contrail 

formation.

Work to date: A pair of ground-based studies in 2009 and 2011 

measured a DC-8’s exhaust emissions as the aircraft burned alternative 

fuels. Flight experiments in 2013 occurred with the sampling HU-25C 

Guardian aircraft flying behind the DC-8. 

Looking ahead: Data collection and analysis will be conducted 

by Langley, and Armstrong will provide the lead aircraft, pilots, and 

airspace. Representatives from Canada and Germany will participate in 

the experiments, as those countries also are interested in wake vortex 

and emissions research. 

Partners: Langley, NRC, and DLR

Benefits

Aids research: Will enable the collection 

of real-time data about engine fumes 

to better understand the chemistry of 

combustion byproducts and aid in the 

evaluation of alternative jet fuels

Reduces pollution: Will contribute to the 

design of cleaner jet engines

Applications

Alternative fuel research

Wake vortex flight research and industrial 

processes
40 ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014

	




%%	


Armstrong’s Research and Engineering Directorate is responsible for the overall 

%%			!%#	#	^"		%	'	#$	 

expertise in aerodynamics; guidance, navigation, and control; propulsion; static and 

	|	!%#	#;		;|	!%#		%				

data systems; and system engineering and integration. They apply their expertise across the 

spectrum of Armstrong’s many activities and also support the development and continual 

evolution of engineering tools and test techniques. Here are highlights from a few recent and 

particularly notable engineering success stories.

Test setup for strain gauge calibration 

$%			#	1&S4	
="
ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014 41

“

Dope on a Rope 2: Development of a 

>	#	
	;	
$			

Armstrong innovators have developed a lifting-body aero tow 

simulation to determine feasibility and procedures for towing the 

Dream Chaser Flight Test Vehicle (FTV) to an altitude of 30,000 

feet. The Dream Chaser FTV is a full-scale, full-weight, singleseat, manned glide test spacecraft and was designed to conduct 

approach and landing tests. The aero tow concept calls for a large 

transport-size jet aircraft to tow a piloted commercial re-entry 

vehicle into the air with a long robust towline. At a predetermined 

altitude, the re-entry vehicle separates from the tow aircraft 

and is landed by the astronaut on board. The tow concept was 

successfully demonstrated in the late 1990s in the Eclipse Project 

with F-106 and C-141 aircraft. 

“Dope on a Rope” was the unofficial Eclipse Project name, a 

moniker developed in jest to teasingly poke fun at the intelligence of 

the project pilot. The name stuck, and “Dope on a Rope 2” has been 

adopted as the unofficial project name for the follow-on work. 

Work to date: The Armstrong team linked an existing simulation 

of the HL-20 lifting-body aircraft and a C-17 to determine feasibility. 

The simulation has been updated with models of the Dream Chaser 

FTV, and a cockpit with representative windows has been built. 

The simulation is now being used to develop tow profiles and 

procedures, evaluate control law changes, and determine potential 

tow vehicles. It is also being used to validate the rope model for 

stability and control analysis.

Looking ahead: An important role of the simulator is to evaluate 

different aircraft as Dream Chaser tow planes. Simulations of 

potential tow aircraft can be linked to evaluate performance and 

tow efficiency. When a tow aircraft is selected, the simulation will be 

used to develop tow techniques and procedures. 

Partners: Sierra Nevada Corporation and U.S. Air Force

As a result of evaluations in the Aero Tow 

Simulator, Sierra Nevada Corporation has 

made Aero Tow the primary method of 

getting the Dream Chaser FTV to altitude 

for the approach and landing testing to 

be performed in 2015-2016. The Aero 

Tow Simulator will play a vital role in 

developing towing techniques and 

procedures, tow mode flight control 

development, and astronaut training. 

Bruce Cogan, PI

”
42 ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014

	




“

%%	




1&		#	}		

Smart Adaptive Flight Effective Cue (SAFE-Cue) is a novel adaptive flight 

control system that provides a means to safely operate an air vehicle in 

the presence of damage or system failures. The system alerts the pilot 

that the adaptive control system is active, provides guidance via force 

feedback cues, and attenuates commands to ensure pilot-vehicle system 

stability and performance in hazardous situations. SAFE-Cue integrates 

diverse disciplines including adaptive compensator design, cockpit inceptor 

design, human operator modeling, and aircraft handling qualities. The 

concept is completely generalized and can be applied to any flight control 

system implementation as a means to mitigate aircraft loss of control. 

The technology was developed under a NASA Small Business Innovation 

Research (SBIR) contract.

Work to date: In 2013, Armstrong test pilots evaluated the SAFE-Cue 

technology on a Calspan variable stability Learjet. The pilots evaluated 

system effectiveness in the presence of pitch and roll axis failures and 

indicated the system successfully eliminated oscillation tendencies that 

can lead to control loss. The technology was also evaluated on the Vertical 

Motion Simulator at NASA’s Ames Research Center. 

Looking ahead: Because the results of both evaluations are promising, the 

Armstrong team will continue to develop and evaluate the technology. Use of 

SAFE-Cue is being considered to make both UAV and lifting-body spacecraft 

such as the Dream Chaser operations safer by implementing loss of control 

and pilot-induced oscillation safeguards as well as assisting in vehicle energy 

management.

Partners: Systems Technology, Inc., under an SBIR contract, and 

subcontractors Barron and Associates and Calspan Corporation

SAFE-Cue provides feedback to a 

pilot via an active control inceptor. 

The system alerts the pilot that the 

adaptive control system is active 

and guides the pilot via force 

feedback cues. 

Bruce Cogan, PI

”


$$&&@P	'~	 

A New Flight Test Technique 

This engineering team has combined two typical flight test techniques into 

a single maneuver enabling crosswind limit calculations, even in calm flight 

conditions. This new and innovative flight test maneuver combines the 

“Steady-Heading Sideslip” and “Bank-to-Bank Roll” maneuvers into a test 

technique the team has named the “Slideslip-to-Bank” maneuver. It is useful 

for simulating crosswinds and for calculating the maximum crosswind limit in 

which a plane can land safely. The team developed the maneuver in order to 

validate a crosswind model for a modified experimental airplane for which no 

crosswind limits were available.

Work to date: During flight tests at 10,000 feet, the team gathered 

high-quality flight data, evaluated aircraft response, and measured trends 

for various crosswind scenarios. The new flight test technique combines 

the “Steady-Heading Sideslip” maneuver, which simulates crosswinds and 

measures rudder effectiveness, and the “Bank-to-Bank” maneuver, which 

collects data along a plane’s rolling axis and validates the rolling model. 

The resulting maneuver is an accurate predictor of residual roll rate capability 

in the presence of sideslip.

Looking ahead: The team would like to perform the maneuver on other 

airplanes to achieve validation.
ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014 43


	
		 

Flight Tests

A technology gap exists between well-controlled wind tunnel 

tests that only examine aerodynamics and full-scale flight 

testing where most systems integration issues surface. The 

Prototype Technology Evaluation Research Aircraft (PTERA) is 

a highly reconfigurable unmanned flight research testbed 

that bridges the gap between wind tunnel and manned flight 

testing with low-cost, low-risk, flight-based evaluation of highrisk technologies. PTERA allows for evaluation of numerous 

advanced aerodynamic configurations, research control laws, 

circulation control systems. Non-structural and replaceable 

leading/trailing edge flaps permit flight evaluation of various 

research high lift and drag reduction technologies. Any UAV 

autopilot and flight control computer can be integrated into the 

platform. 

All PTERA data and models are open source and available to 

the entire flight research community. There are no publication 

restrictions on flight test results and no aircraft proprietary data.

Work to date: PTERA flew for the first time in July 2012, and 

the focus was on system testing, pilot familiarization, and initial 

performance measurements. In 2013, PTERA flew an additional 

six flights. Primary focus was on system identification to develop 

aero models and to evaluate stall characteristics. Tao sensors 

were also flown on these flights as part of a NASA Aeronautics 

Research Mission Directorate Seedling Fund research effort. 

Looking ahead: A PTERA aircraft will arrive at Armstrong in 

fall 2014. Several flight research experiments have already been 

identified.

Partner: Area-I, Inc., developed the PTERA testbed under 

the NASA SBIR program. Other partners include the State of 

Georgia, Georgia Tech Research Institute, Middle Georgia State 

College, Solid Concepts, and Aeroprobe Corporation.

“

”

This research platform provides an 

affordable bridge between wind tunnel 

and full-scale testing to mature new 

aircraft technologies through flight test 

and evaluation.

Bruce Cogan, PI
44 ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014

	


 %%	



(}"""	#	'			%

The Orion Abort Flight Test (AFT) team at Armstrong led the vehicle 

integration and operations effort for the Orion Pad Abort 1 (PA-1) flight 

test, which occurred at the White Sands Missile Range (WSMR) in May 

2010. PA-1 was the first fully integrated flight test of the Launch Abort 

System (LAS), one of the primary systems within the Orion MultiPurpose Crew Vehicle (MPCV). The LAS provides the crew with an 

escape capability in the unlikely event of an emergency on the launch 

pad or during mission vehicle ascent. While the Orion Crew Module (CM) 

was at Armstrong, engineers and technicians installed instrumentation, 

electrical wiring, computer systems, avionics, parachutes, thermal 

ducting, acoustic blankets, and a GPS/inertial navigation system. 

Vibration and acoustics tests of the Orion CM assessed the effects of 

an abort motor firing on both the structure and internal electronics. A 

combined systems test verified the flight readiness of the flight control, 

antenna, pyrotechnic, and ground control systems.

After the Orion CM was transferred to WSMR, Armstrong expanded its 

lead of the integration and operations effort, mating the Orion CM with 

the Orion LAS, followed by the mission operations activity for the highly 

successful PA-1 flight test.

Work to date: The Orion PA-1 Flight-Test Vehicle integration and 

operations effort required a significant contribution from the Armstrong 

workforce, and ultimately culminated in the successful demonstration of 

an abort capability from the launch pad. Information learned during PA-1 

will help certify and refine the LAS design for future human spaceflight 

missions.

Looking ahead: The Orion LAS is a primary system within the 

Orion MPCV, which is now part of the NASA Space Launch System 

(SLS) architecture. The SLS will be used to transport astronauts to 

destinations beyond low Earth orbit. Future flight testing (beyond PA-1) 

will ensure abort capability for the SLS.

Partners: NASA’s Johnson Space Center, Langley Research Center, 

and Marshall Space Flight Center and the Lockheed Martin Corporation

“ The Orion PA-1 flight was the first fully 

integrated test of the Orion LAS design. 

Had this flight abort occurred during launch 

preparations for a real human spaceflight 

mission, the PA-1 LAS would have saved 

the lives of the crew.

Daniel Jones

Former Orion AFT propulsion lead 

”
ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014 45

($	>	
I	
	6>
7~	

P%		$			

Armstrong’s PDAT technology offers a versatile solution for displaying 

and archiving data in real time at remote locations. Developed to collect 

data from strain gauges and fiber optic sensors as part of the Adaptive 

Compliant Trailing Edge (ACTE) project, the technology easily supports 

other experiments by means of interchangeable hardware cards that collect 

data from pressure transducers, pressure scanners, and accelerometers. 

It has already been used in Armstrong’s Flight Loads Laboratory (FLL) 

and in industry laboratories in Michigan and California to support ACTE 

research. PDAT can be quickly reprogrammed to support various tests and 

can display and archive data from virtual streams. This portable and flexible 

technology supports remote data collection for field experiments where 

there is not a lot of room to work and where live transmission is limited.

Work to date: In addition to its use in Armstrong’s FLL and in industry 

laboratories, the PDAT provided designers with valuable feedback data 

during the construction and design phase of the ACTE project. The system 

safely gathered data from the aircraft system during wing loads testing 

without the need to turn on aircraft power. PDAT data were verified against 

the loads system data to assure system accuracy.

Looking ahead: This unique system has 64 channels for analog data, 

32 channels for thermocouples, and eight signal conditioning cards. It is 

currently configured to gather strain gauge and thermocouple inputs, but 

a host of other hardware can be installed, making the system versatile 

enough to become a successful component of current and future projects.

“ The PDAT system was designed to 

be both portable and flexible and 

address frequent requests for a 

small system to collect and archive 

data on and off aircrafts. Possible 

uses are endless.

Nikki Martin

Instrumentation Engineer

”

!($	
	%

Unique equipment at Armstrong’s Flight Loads Laboratory (FLL) 

has enabled researchers to conduct mechanical loads testing on 

the Hypersonic Inflatable Aerodynamic Decelerator (HIAD) test 

articles. The HIAD is the spacecraft technology designed to provide 

deceleration to vehicles entering into an atmospheric environment 

from space. Comprised of a series of inflated tori (resembling a 

giant cone of inner tubes), the HIAD will deploy to slow down a 

spacecraft as it enters the atmosphere. Benefits of using the inflatable 

decelerator design include mission flexibility provided by the minimal 

volume and mass requirements to transfer the stowed HIAD to its 

destination, as well as increased landed mass, accuracy, and altitude 

in a variety of space applications. Armstrong researchers used 

specialized testing equipment at the FLL to characterize structural 

properties of the HIAD tori for finite element model (FEM) validation. 

Work to date: The hydraulic loading system in Armstrong’s FLL 

enabled researchers to impose torsion and compression loads on the 

torus test articles through a series of pulleys and cables. The team 

evaluated eight test articles, and the data is being analyzed by NASA’s 

Langley Research Center.

NASA Partner: Langley Research Center

“

”

The HIAD testing at Armstrong’s Flight 

Loads Laboratory contributed to the 

Agency’s space technology development. 

The data obtained will help engineers 

design better space decelerators that will 

meet the future mission requirement.

Tony Chen, PI
46 ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014

	


 %%	


%	#	@

NASA and industry partners are working to develop technologies that 

will reduce the noise and annoyance associated with sonic booms 

so that aviation authorities can consider lifting the prohibitions on 

overland supersonic air travel. An Armstrong research team is designing 

and executing tests to record various aspects of sonic booms. The 

tests capture numerous aircraft boom signatures through innovative 

recording methods, planning, and piloting techniques and are primarily 

used to advance NASA’s understanding of how booms are formed and 

propagated. 

Work to date: The Armstrong team and a number of industry partners 

have identified and validated several methods and techniques for 

capturing and measuring sonic booms. A notable method is the Boom 

Amplitude and Direction Sensor (BADS), which employs six pressure 

transducers widely spaced on the vertices of an octahedron. Similarly, 

Supersonic Notification of Over Pressure Instrumentation (SNOOPI), 

an all-weather pressure transducer system, records local sonic booms 

by date, time, and intensity, 24-hours a day, 7 days a week. This test 

equipment, in conjunction with more traditional microphones, is used 

to record sonic booms generated through special piloting techniques 

specifically designed for sonic boom placement and mitigation. From 

these methods and techniques, the Armstrong team has collected test 

data from various projects to determine how F/A-18 dive maneuvers may 

create lower-level and focused booms.

Looking ahead: The team will continue to advance NASA’s 

understanding of sonic boom phenomena via sonic boom tests and data 

analysis. This includes potential research in atmospheric turbulence 

effects on sonic booms and community response to low booms. These 

activities will play a key role in the testing of an anticipated low-noise 

sonic boom flight demonstrator aircraft.

Partners: Japan Aerospace Exploration Agency (JAXA), Dassault 

Aviation, Gulfstream, The Boeing Company, Pennsylvania State 

University, Wyle, Cessna Aircraft Company, NASA’s Langley Research 

Center, and NASA’s Marshall Space Flight Center

“ NASA Armstrong captures a variety of 

aircraft sonic boom signatures through 

innovative recording methods, planning, 

and piloting. 

Edward Haering, PI

”
ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014 47

Flying an Airplane Like a Rocket 

NASA Armstrong’s high-performance F/A-18 Full-Scale Advanced 

Systems Testbed (FAST) aircraft was key to helping test and validate the 

effectiveness of innovative self-adaptive software being considered for 

use in the next-generation Space Launch System (SLS). Developed by 

engineers at Marshall Space Flight Center, the SLS rocket will be NASA’s 

largest and most powerful launch vehicle for deep space missions. The 

adaptive software is designed to make real-time adjustments as a vehicle 

pushes toward space, helping to improve rocket performance and enhance 

crew safety in the particularly stressful launch portions of flight. The team 

installed SLS flight control software onto research computers aboard the 

FAST aircraft and simulated a rocket in its early flight phase to test the 

adaptive control software. The FAST aircraft’s high performance allowed 

it to fly a trajectory that was dynamically similar to a rocket launch. This 

collaborative project yielded a major advance in launch vehicle flight 

control technology and substantially accelerated the application of 

adaptive control to manned systems.

Work to date: Flight tests occurred at Armstrong in late 2013. During 

these flights, almost 100 SLS trajectories and over a dozen straight-andlevel airframe structural amplification tests were successfully executed, 

many of which focused on collecting additional data regarding the 

interaction of the pilot, the simulated SLS vehicle dynamics, and the 

adaptive augmenting control algorithm. 

Looking ahead: The team is analyzing flight data and considering ways 

to apply similar technology to aircraft and atmospheric re-entry vehicles.

NASA Partners: Marshall Space Flight Center and NASA Engineering 

and Safety Center

The goal of the F/A-18 flights was to 

advance the technology readiness of the 

SLS adaptive control design by operating 

it in a relevant environment while introducing a wide variety of unusual launch 

scenarios. Test pilots also exercised the 

SLS controller’s manual steering mode, 

providing valuable feedback on its design 

and performance. 

Curtis Hanson, PI

“

”

P%	#	
		
%	#	($

Innovative hardware upgrades to Armstrong’s Airborne Schlieren Imaging 

System (ASIS) are improving reliability and precision. The ASIS platform captures 

shockwave images by aligning a supersonic aircraft between a camera-equipped 

aircraft and the sun, and then watching as the shocks put an apparent ripple 

on the sun’s edge. The technique enables researchers to validate data from 

supersonic models and wind tunnel tests. Armstrong engineers recently designed 

and implemented adjustments to the ASIS Forward-Looking Infrared (FLIR) 

camera pod to improve its performance. 

Work to date: Innovators developed highly precise solar masks that block all but 

the very edge of the sun. Since the apparent solar radius changes throughout the 

year due to Earth’s changing proximity to the sun, the team created two masks 

that are 0.001 inches different in radius—one for a summer mean radius and 

another for a winter mean. A programmable tooling machine made manufacturing 

the masks straightforward; the harder challenge was inspecting them. The 

team employed a laser projection device to create well-defined and accurately 

enlarged mask images, enabling small radial measurements. The group also 

used borescopes to view a “blind” connector that did not fully mate during pod 

assembly, causing routine flight vibrations to induce intermittent system failures. A 

new connector scheme allows for a more robust and fully mated connection.

Looking ahead: The team will continue to test and mature the technology and to 

identify potential research partners.

Armstrong has the tools, ingenuity, and skills on hand to tackle 

difficult problems. The ASIS team 

made full use of these skills when 

developing and improving the 

system. We look forward to 

obtaining elusive aircraft shock 

visuals with this equipment. 

Paul Bean, PI

“

”
48 ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014

“

”

	


 %%	


Precision Path Autopilot (PPA) 

There is a growing need for accurate measurements to assist in the 

study and understanding of dynamically changing Earth deformations 

resulting from disasters such as earthquakes, volcanic activity, and 

polar ice cap changes. Armstrong’s PPA flight control system enables an 

aircraft to repeatedly fly nearly the same trajectory hours, days, or weeks 

later to obtain these measurements. The PPA consists of an embedded 

microcontroller-based flight computer and navigation algorithms that 

use externally provided attitude and differential GPS information to 

generate aircraft control commands. The system features a unique use 

of a controller area network (CAN) system and design interface to imitate 

an instrument landing system (ILS) and enable precise, repeat-pass 

flights.

Work to date: The technology was developed for NASA’s Unmanned 

Aerial Vehicle Synthetic Aperture Radar (UAVSAR) program, which 

requires flight path repeatability. At 300-600 knots groundspeed, the 

PPA reliably keeps an aircraft within a 5-meter radius of a fixed line 

through space, whether the line is 30 or 200 miles long. This capability 

allows precise, repeat-pass interferometry for the UAVSAR program. The 

system has been used since 2007 in field science missions over Mount 

St. Helens, South America, Greenland, Iceland, Alaska, Japan, and all of 

California and Hawaii.

Looking ahead: The team continues to support the UAVSAR 

program in its science missions.

The PPA system was designed, built, 

tested, and deployed at Armstrong. The 

supporting graphic displays and the pilot 

expertise required to efficiently collect 

data are key to its success. The system 

has successfully supported the UAVSAR 

program in many science missions. 

Sean Clarke and 

Brian Strovers, PIs

The Orion Abort Flight Test team 

at the White Sands Missile Range, 

May 2010.
ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014 49

Appendix

Hyperelastic Research/Lightweight 

Flexible Aircraft

Adaptive Compliant Trailing Edge (ACTE) 

Flight Experiment

Ethan Baumann 

661-276-3417 | Ethan.A.Baumann@nasa.gov 

Fundamental Hyperelastic Material Study

Eric Miller 

661-276-7041 | Eric.J.Miller@nasa.gov

Additional Information:

Streett, C. L.; Casper, J. H.; Lockard, D. 

P.; Khorrami, M. R.; Stoker, R.W.; Elkoby, 

R.; Wenneman W. F.; Underbrink, J. R.; 

|'&	
;


:
}+<:



Devices on a Swept Wing Model,” 44th AIAA 

Aerospace Science Meeting and Exhibit, Reno 

;$^
'''
~~~^
~

X-56A Multi-Utility Technology Testbed 

(MUTT) 

John Bosworth 

661-276-3792 | John.T.Bosworth@nasa.gov


	
	

	


	



	


X-56A Model 

Peter Suh 

661-276-3402 | Peter.M.Suh@nasa.gov

Real-Time Structural Overload Control via 

Control Allocation Optimization

Chris Miller 

661-276-2902 | Chris.J.Miller@nasa.gov 

Inverse Finite Element Method (iFEM) 

Investigation for Adaptive Structures

Eric Miller 

661-276-7041 | Eric.J.Miller@nasa.gov

Active Control of Tailored Laminates

Chris Kostyk 

661-276-5443 | Chris.B.Kostyk@nasa.gov

Active/Adaptive Flexible Motion Controls with 

Aeroservoelastic System Uncertainties

Chan-gi Pak 

661-276-5698 | Chan-Gi.Pak-1@nasa.gov

Flight and Ground Experimental Test 

Technologies


	
		


Mark Smith 

661-276-3177 | Mark.S.Smith@nasa.gov


		




!"

Clinton St. John 

661-276-5306 | Clint.W.St.John@nasa.gov

#
	
$	
$	



Alex Chin 

661-276-2681 | Alexander.W.Chin@nasa.gov

Additional Information:

K

^
!^
|+
&


#
&


Estimation Using the Dynamic Inertia Method,” 

Master’s Thesis, University of Cincinnati, 2000.

Lazor, D.R., “Considerations for Using the 

Dynamic Inertia Method in Estimating Rigid 

&


#
&^

]
^


University of Cincinnati, 2004.

ATA Engineering, Inc., “Final Report on 

Dynamic Inertia Measurement Method 


+^
''
#

;
~^
;$	J


17, 2010.


	

	




%	


Monitoring

Devin Boyle 

661-276-2443 | Devin.K.Boyle@nasa.gov

%
	
&

	

	

Larry Hudson 

661-276-3925 | Larry.D.Hudson@nasa.gov

	


	

!'"
*


Enhancements

CJ Bixby 

661-276-3394 | Cynthia.J.Bixby@nasa.gov

Fiber Optic Sensing

Compact FOSS (cFOSS)

Allen Parker 

661-276-2407 | Allen.R.Parker@nasa.gov
50 ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014

Additional Information:

;''



#



:




technology portfolio (U.S. Patent 7,715,994, 

U.S. Patent 7,520,176, and U.S. Patent 

8,700,358).

Emmons, Michael C.; Sunny Karnani; Stefano 

Trono; Kotekar P. Mohanchandra; W. Lance 

Richards; and Gregory P. Carman; (2010) 

“Strain Measurement Validation of Embedded 

*J
++
@
+^




:


Optomechatronics, 4:1, 22-33.

Mohanchandra, K.P.; S. Karnani; M.C. 

Emmons; W.L. Richards; and G.P. Carman; 

|
*	
;

!
+

=#

*J


++
^
'##
&
<





03194 (2008).

Hybrid FOSS (HyFOSS)

Allen Parker 

661-276-2407 | Allen.R.Parker@nasa.gov 

Patrick Chan 

661-276-6170 | Hon.Chan@nasa.gov

Smart Sensing Using Wavelets

Philip Hamory 

661-276-3090 | Philip.J.Hamory@nasa.gov

	

+

	
,	
0	


Measurements

Lance Richards 

661-276-3562 | Lance.Richards-1@nasa.gov

0	
0


	

 

,


!1"
0

Lance Richards 

661-276-3562 | Lance.Richards-1@nasa.gov

Cryogenic FOSS (CryoFOSS)

Allen Parker 

661-276-2407 | Allen.R.Parker@nasa.gov

High-Temperature Strain Sensing

Anthony Piazza 

661-276-2714 | Anthony.Piazza-1@nasa.gov

Strain Sensing for Highly Elastic Materials

Anthony Piazza 

661-276-2714 | Anthony.Piazza-1@nasa.gov

Health Monitoring of Flight Structures

Larry Hudson 

661-276-3925 | Larry.D.Hudson@nasa.gov

Supersonic Flight Research 

0

*


$	
2

Larry Cliatt 

661-276-7617 | Larry.J.Cliatt@nasa.gov


3	
		7
0

*


#


7

!0*

"

Edward Haering 

661-276-3696 | Edward.A.Haering@nasa.gov

8
7		



:
*






!8:"

Edward Haering 

661-276-3696 | Edward.A.Haering@nasa.gov

0

*
#
+#
	




!0*+
"

Dan Banks 

661-276-2921 | Daniel.W.Banks@nasa.gov

	

*3
;	
0


!*;0"

Daniel Banks 

661-276-2921 | Daniel.W.Banks@nasa.gov 

Airborne Schlieren Imaging System (ASIS)

Paul Bean 

661-276-2451 | Paul.Bean@nasa.gov

Collision Avoidance Technologies

&

7	

	
	7





0#	
!&0"

Loyd Hook 

661-276-5714 | Loyd.Hook-1@nasa.gov

Improved Ground Collision Avoidance System 

!&0"


<

Mark Skoog 

661-276-5774 | Mark.A.Skoog@nasa.gov

Multi-Level Autonomous Piloting System 

(MAPS)

Loyd Hook 

661-276-5714 | Loyd.Hook-1@nasa.gov
ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014 51

Avionics and Instrumentation 

Technologies

Platform Precision Autopilot (PPA)

Matt Redifer 

661-276-2694 | Matt.E.Redifer@nasa.gov

	
	
	
07
*
	


!0*"
0#	



0		



Awareness

Ricardo Arteaga 

661-276-2296 | Ricardo.A.Arteaga@nasa.gov

		

		
0



Control

Martin Brenner 

661-276-3793 | Martin.J.Brenner@nasa.gov


	
	
2	

0#
!"

Shedrick Bessent 

661-276-3663 | Shedrick.B.Bessent@nasa.gov

:	,
3
			


Russell Franz 

661-276-2022 | Russell.J.Franz@nasa.gov

Airborne Research Test System, Fourth 

&	

!0
"

Chris Miller 

661-276-2902 | Chris.J.Miller@nasa.gov

:>	&	


	8	





#
,	
	
$


	

Glenn Sakamoto 

661-276-3679 | Glenn.M.Sakamoto@nasa.gov

Hypersonics and Space Technologies

Air Launch from a Towed Glider

Jerry Budd 

661-276-3377 | Gerald.D.Budd@nasa.gov

Additional Information:

;''

##
:

#


:




technology (Patent Application 13/573,920, 

“System and Method for an Air Launch from a 

Towed Aircraft,” March 2013).

Wilhite, Alan, “Value Proposition of a Towed-

@
<
&
	^
;





:


Aerospace, October 2012.

|#
#^
'$

K"

#


Technology, January 2013.

“Gliding to Space: A novel means of launching 

#


^
'

;>

$>^


March 2013.

		

	
:
??
!:"

Daniel Jones 

661-276-3498 | Daniel.S.Jones@nasa.gov

Additional Information:

^
%

+



#
}


:
|#
*+


:

%


"

;BB
+


;''
*
'#^


AIAA 2013-3954, July 2013.

^
%

+



#
}


:
|'

!	#
+
;BB
'!;


\
Y
+
:
%
"

;BB


*+


+



;''
*^
#



;	J
%*!%'';^
&
~

Advanced Control Method for Hypersonic 



John Burken 

661-276-3726 | John.J.Burken@nasa.gov

Additional Information:

;+&^
<


K	

@J


&


E. Ogburn; “Control-System, Techniques 

for Improved Departure Spin Resistance for 

*+

':
^
;''

^
'+



"^


+
<
+
K



!
&
	
|>
:+J


Flight-Control Design Methods: Robust 

Servomechanism and Control Allocation,” 

Journal of Guidance, Control, and Dynamics, 


~^
;
^
&
~

+^
#+


:
	


!++
K+

%





“Retrospective Cost Model Refinement for 

On-Line Estimation of Constant and Time-

&+
*+

	
^
'''
@;!
~


^
%
^
|"








Retrospective Cost Adaptive Control (RCAC) 

for Plants with Uncertain Dynamics and 

Disturbance Spectra,” March 2012.

Adaptive Guidance Algorithms for 

Hypersonics

Oscar Murillo 

661-276-6110 | Oscar.J.Murillo@nasa.gov
52 ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014

High-Altitude Atmospheric Reconstruction

Edward Teets 

661-276-2924 | Edward H. Teets@nasa.gov

Structurally Integrated Thermal Protection 

System (SITPS)

Craig Stephens 

661-276-2028 | Craig.A.Stephens@nasa.gov

Efficient Aerospace Vehicle 

Technologies

:+
00
&


Al Bowers 

661-276-3618 | Albion.H.Bowers@nasa.gov

Additional Information:


^
'^
|K

%
*+






J
$^


#Y>>>&
J	

>
$&K$?>}'^
~

;''

##
:

#


:




technology.


	
		



	


Stand

Sean Clarke 

661-276-2930 | Sean.Clarke@nasa.gov

Additional Information:

K>"^
@	^
|@+

Y
;''


%&

+

J


'$


Understanding of Electric Propulsion for 

':
^
'$

K"

#
+&^


September 2013.

Warwick, Graham, “Turboelectric Propulsion 


#
+

;

'$

K"



Space Technology, March 2012.

Kim, Hyun Dae, “Distributed Propulsion 

Vehicles,” Proceedings of 27th International 

!+
:


'

^
;^


France, September 2010.

<



<

Ryan Dibley 

661-276-5324 | Ryan.P.Dibley@nasa.gov

	

<



Ryan Dibley 

661-276-5324 | Ryan.P.Dibley@nasa.gov

	
8

	

		

	>
+
	






	


8
	

8	

Jack Ryan 

661-276-2558 | John.J.Ryan@nasa.gov

Optimized Lift for Autonomous Formation 

Flight (OLAFF)

Curtis Hanson 

661-276-3966 | Curtis.E.Hanson@nasa.gov

Peak-Seeking Control for Trim Optimization

Nelson Brown 

661-276-5039 | Nelson.A.Brown@nasa.gov

Low-Carbon Propulsion Technology

Alternative Fuels’ Effects on Contrails and 

Cruise Emissions (ACCESS) Flight Experiment

Brian Strovers 

661-276-5415 | Brian.K.Strovers@nasa.gov

Engineering Successes








1@
7
	






Chaser Aero Tow Simulation

Bruce Cogan 

661-276-2627 | Bruce.R.Cogan@nasa.gov

SAFE-Cue to the Rescue!

Bruce Cogan 

661-276-2627 | Bruce.R.Cogan@nasa.gov

0	
*3
$7@

:,
8	
	


2

Troy Asher 

661-276-6125 | Troy.A.Asher@nasa.gov 


0#	
		

8	
	

Bruce Cogan 

661-276-2627 | Bruce.R.Cogan@nasa.gov

Abort!...In the Event of an Emergency

Daniel Jones 

661-276-3498 | Daniel.S.Jones@nasa.gov

Additional Information:

Williams-Hayes, Peggy S.; “Crew Exploration 

Vehicle Launch Abort System Flight Test 

Overview,” AIAA 2007-6596, August 2007. 
ARMSTRONG RESEARCH, TECHNOLOGY, AND ENGINEERING ACCOMPLISHMENTS 2014 53

Idicula, Jinu; Peggy S. Williams-Hayes; 

&

>


<

?


|'
*+



Dynamics Perspective of the Orion Pad Abort 

One Flight Test,” AIAA 2009-5730, August 

2009. 

Kutty, Prasad M.; and William D. Pratt; “The 

Range Safety Debris Catalog Analysis in 

Preparation for the Pad Abort One Flight Test,” 

AIAA 2010-0668, January 2010. 

Houtas, Franzeska F.; and Edward H. Teets; 

“Lidar Wind Profiler Comparison to Weather 


:
##

:
=
!>
?#




<+^
;''~~^


February 2010. 

Stillwater, Ryan A.; “Pitch Guidance 

Optimization for the Orion Abort Flight Tests,” 

AIAA 2010-7516, August 2010. 

Herrera, Claudia; and Adam Harding; “Orion 

Pad Abort 1 Crew Module Mass Properties 

Test Approach and Results,” AIAA 2012-1396, 

April 2012. 

Jones, Daniel S.; Syri J. Koelfgen; Marvin 

K



!&
&



K

%


!
+
%


“Executive Summary of Propulsion on the 

Orion Abort Flight-Test Vehicles,” AIAA 2012-

3891, July 2012. 

'^
'&
;

&
<

|'&


and Results from a Flush Airdata Sensing 

System in Close Proximity to Firing Rocket 

;BB^
'''
~^
'+

~


	
	
2	

0#
!"@


Making Ideas Reality

Nikki Martin 

661-276-3112 | Nikki.L.Martin@nasa.gov

D	
0		
	

Tony Chen 

661-276-2336 | Tony.Chen-1@nasa.gov

	
	
*



Edward Haering 

661-276-3696 | Edward.A.Haering@nasa.gov

Flying an Airplane Like a Rocket

Curtis Hanson 

661-276-3966 | Curtis.E.Hanson@nasa.gov

Masking the Sun and Scoping the Problem

Paul Bean 

661-276-2451 | Paul.Bean@nasa.gov

Precision Path Autopilot (PPA)

Sean Clarke 

661-276-2930 | Sean.Clarke@nasa.gov

Brian Strovers 

661-276-5415 | Brian.K.Strovers@nasa.gov

All photos owned by NASA except: upper right image page 13: Getty Image, upper right image page 15: Getty image (same image appears on cover), upper left image 

page 18: Getty image, lower left image page 28: Getty image, and upper left image page 46: NASA/Boeing image, all images on page 48: Area-I, Inc.


Armstrong Flight Research Center

P.O. Box 273

Edwards, CA 93523-0273

www.nasa.gov